 # Final Practice 1

A truck is moving at constant velocity. Inside the storage compartment, a rock is dropped from the midpoint of the ceiling and strikes the floor below. The rock hits the floor

A) exactly below the midpoint of the ceiling.
B) ahead of the midpoint of the ceiling.
C) behind the midpoint of the ceiling.
E) none of these

A) exactly below the midpoint of the ceiling.

test 1

If your automobile runs out of fuel while you are driving, the engine stops but you do not come to an abrupt stop. The concept that most explains why is

A) inertia.
B) gravity.
C) acceleration.
D) resistance.

A) inertia.

test 1

Whirl a rock at the end of a string and it follows a circular path. If the string breaks, the tendency of the rock is to

A) continue to follow a circular path.
C) increase its speed.
D) revolve in a smaller circle.

test 1
Practice test 1
homework 2

According to Newton’s law of inertia, a railroad train in motion should continue going forever even if its engine is turned off. We never observe this because railroad trains

A) move too slowly.
B) are much too heavy.
C) must go up and down hills.
D) always have forces that oppose their motion.

D) always have forces that oppose their motion.

test 1
practice test 1
homework 2

If no external forces are acting on a moving object, it will

A) continue moving at the same speed.
B) continue moving at the same velocity.
C) move slower and slower until it finally stops.

B) continue moving at the same velocity.

test 1

Which of the following is not a vector quantity?

A) Speed
B) velocity
C) acceleration
D) all are vector quantities

A) Speed

test 1
homework 3

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An airplane flies at 100km/h in still air. If it flies into a 10 km/h headwind, its groundspeed is

A) 100 km/h
B) 110 km/h
C) 120 km/h
D) 90 KM/h

D) 90 km/h

100 km/h – 10 km/h = 90 km/h

test 1
homework 3

A car maintains a constant velocity of 100 km/hr for 10 seconds. During this interval its acceleration is

A) zero.
B) 10 km/hr.
C) 110 km/hr.
D) 1000 km/hr.

A) zero.

If velocity is constant than acceleration is 0

test 1

While an object near the Earth’s surface is in free fall, its

A) velocity increases.
B) acceleration increases.
C) mass increases.
D) mass decreases.

A) velocity increases.

test 1

A hockey puck is set in motion across a frozen pond. If ice friction and air resistance are neglected, the force required to keep the puck sliding at constant velocity is

A) zero.
B) equal to its weight divided by its mass.
C) equal to the product of its mass times its weight.

A) zero.

objects in motion stay in motion

test 1

If an object falling freely were somehow equipped with an odometer to measure the distance it travels, then the amount of distance it travels each succeeding second would be

A) constant.
B) less and less each second.
C) greater than the second before.
D) doubled.

C) greater than the second before.

test 1

If a car accelerates from rest at 2 meters per second per second, its speed 3 seconds later will be about

A) 2 m/s.
B) 3 m/s.
C) 4 m/s.
D) 6 m/s.

D) 6 m/s.

2m/s * 3s = 6m/s

test 1

A ball is thrown upwards and returns to the same position. Compared with its original speed after release, its speed when it returns is about

A) half as much.
B) the same.
C) twice as much.
D) four times as much.

B) the same.

test 1

At one instant an object in free fall is moving downward at 50 meters per second. One second later its speed should be about

A) 25 m/s.
B) 50 m/s.
C) 55 m/s.
D) 60 m/s.
E) 100 m/s.

D) 60 m/s.

g is 10 m/s
50 m/s + 10 m/s

test 1

It takes 6 seconds for a stone to fall to the bottom of a mine shaft. How deep is the shaft?

D) more than 200 m

ut + 0.5at²
(0 * 6) + (0.5 * 10 * 6²)
0 + 180
180

If a projectile is fired straight up at a speed of 10 m/s, the time it takes to reach the top of its path is about

A) 1 second.
B) 2 seconds.
C) 10 seconds.
D) not enough information to estimate

A) 1 second.

g is 10 m/s. Going up an object would lose 10 m/s

test 1

When a rock thrown straight upwards gets to the exact top of its path, its

A) velocity is zero and its acceleration is zero.
B) velocity is zero and its acceleration is about 10 meters per second per second.
C) velocity is about 10 m/s and its acceleration is zero.
D) velocity is about 10 m/s and its acceleration is about 10 meters per second per second.
E) none of these

B) velocity is zero and its acceleration is about 10 meters per second per second.

test 1
Practice test 1
homework 3

A car accelerates from rest for 5 seconds until it reaches a speed of 20 m/s. What is the car’s acceleration in meters per second per second?

A) 1
B) 2
C) 3
D) 4
E) 5

D) 4

test 1

A bullet is dropped into a river from a very high bridge. At the same time, another bullet is fired from a gun, straight down towards the water. Neglecting air resistance, the acceleration just before striking the water

A) is greater for the dropped bullet.
B) is greater for the fired bullet.
C) is the same for each bullet.
D) depends on how high they started.
E) none of these

C) is the same for each bullet.

test 1

Distance is to displacement as

A) speed is to velocity
B) impulse is to momentum
C) force is to weight
D) velocity is to acceleration
E) none of the above choices are correct

A) speed is to velocity

test 1
homework 3

A kilogram is a measure of an object’s

A) weight
B) size
C) force
D) mass

D) mass

test 1
homework 4

Compared to a 1-kg block of solid iron, a 2-kg block of solid iron has the same

A) mass.
B) volume.
C) weight.
D) all of these
E) none of these

E) none of these

test 1

B) the gravitational attraction force between you and the Earth.
C) a property of mechanical equilibrium.
D) all of these

B) the gravitational attraction force between you and the Earth.

test 1
homework 4

Compared to the mass of a certain object on Earth, the mass of the same object on the moon is

A) one sixth as much.
B) the same.
C) six times as much.
D) zero.

B) the same.

test 1
homework 4

An object’s weight may properly be expressed in units of

A) meters.
B) kilograms.
C) newtons.
D) cubic centimeters.

C) newtons.

test 1
practice test 1

A force is a vector quantity because it has both

A) magnitude and direction.
B) mass and acceleration.
C) action and reaction counterparts.

A) magnitude and direction.

test 1
homework 4

A 10-kg brick and a 1-kg book are dropped in a vacuum. The force of gravity on the 10-kg brick is

A) the same as the force on the 1-kg book.
B) 10 times as much.
C) one-tenth as much.
D) zero.

B) 10 times as much.

test 1

If an object’s mass is decreasing while a constant force is applied to the object, the acceleration

A) decreases.
B) increases.
C) remains the same.

B) increases.

test 1
homework 4

An object is pulled northward by a force of 10 N and at the same time another force of 15 N pulls it southward. The magnitude of the resultant force on the object is

A) 0 N.
B) 5 N.
C) 25 N.
D) 150 N.

B) 5 N.

15 N south – 10 N north

test 1

An apple weighs 1 N. When held at rest above your head, the net force on the apple is

A) 0 N.
B) 0.1 N.
C) 1 N.
D) 9.8 N.
E) none of these

A) 0 N.

test 1

Which has zero acceleration? An object

A) at rest.
B) moving at constant velocity.
C) in mechanical equilibrium.
D) all of these
E) none of these

D) all of these

test 1

A heavy block at rest is suspended by a vertical rope. When the block is accelerated upward by the rope, the rope tension

A) increases.
B) decreases.
C) remains the same.

A) increases.

test 1
homework 4

A car has a mass of 1000 kg and accelerates at 2 meters per second per second. What is the magnitude of the net force exerted on the car?

A) 500 N
B) 1000 N
C) 1500 N
D) 2000 N
E) none of these

D) 2000 N

F = ma * 2 = 2000 N

test 1

A bag of groceries has a mass of 10 kilograms and a weight of

E) more than 1000 N.

test 1

A 10-N block and a 1-N block lie on a horizontal frictionless table. To provide them with equal horizontal acceleration, we would have to push with

A) equal forces on each block.
B) 10 times as much force on the heavier block.
C) 10 squared or 100 times as much force on the heavier block.
D) 1/10 as much force on the heavier block.
E) none of these

B) 10 times as much force on the heavier block.

test 1

Suppose a particle is being accelerated through space by a 10-N force. Suddenly the particle encounters a second force of 10 N in the opposite direction from the first force. The particle with both forces acting on it

A) is brought to a rapid halt.
B) decelerates gradually to a halt.
C) continues at the speed it had when it encountered the second force.
D) theoretically tends to accelerate toward the speed of light.
E) none of these

C) continues at the speed it had when it encountered the second force.

The first force causes acceleration the second force cancels the acceleration. It would take a another force to make the object stop

test 1

A 1-kg ball is thrown at 10 m/s straight upward. Neglecting air resistance, the net force that acts on the stone when it is halfway to the top of its path is about

A) 1/2 N.
B) 1 N.
C) 5 N.
D) 7.5 N.
E) 10 N.

E) 10 N.

test 1

A skydiver of mass 100 kg experiences air resistance of 600 N, and an acceleration of

A) 6 m/s^2
B) 3 m/s^2
C) 500 m/s^2
D) 4 m/s^2
E) 10 m/s^2

D) 4 m/s^2

test 1

If you are driving at 20 m/s and slam on your brakes and skid at 0.5 g to a full stop, the skidding time in seconds is

E) more than 6.

test 1

A 2000-kg car experiences a braking force of 8,000 N and skids to a stop in 5 seconds. The speed of the car just before the brakes were applied was

A) 20 m/s.
B) 1.25 m/s.
C) 300 m/s.
D) 45 m/s.
E) none of these

A) 20 m/s.

(8000/2000) * 5

test 1

If an object of constant mass experiences a constant net force, it will have a constant

A) velocity.
B) speed.
C) acceleration.
D) position.
E) more than one of the above

C) acceleration.

test 1

If more horizontal force is applied to a sliding object than is needed to maintain a constant velocity

A) the object accelerates in the direction of the applied force.
B) the object accelerates opposite the direction of the applied force.
C) the friction force increases.
D) two of the above
E) none of the above

A) the object accelerates in the direction of the applied force.

test 1

A skydiver, who weighs 500 N, reaches terminal velocity of 90 km/h. The air resistance on the diver is then

A) 90 N.
B) 250 N.
C) 410 N.
D) 500 N.
E) none of these

D) 500 N.

test 1

A feather and a coin will have equal accelerations when falling in a vacuum because

A) their velocities are the same.
B) the force of gravity is the same for each in a vacuum.
C) the force of gravity does not act in a vacuum.
D) the ratio of each object’s weight to its mass is the same.
E) none of these

D) the ratio of each object’s weight to its mass is the same.

test 1

Wherever there is an action force, there must be a reaction force that

A) always acts in the same direction.
B) is slightly smaller in magnitude than the action force.
C) is slightly larger in amplitude than the action force.
D) is exactly equal in magnitude.

D) is exactly equal in magnitude.

test 1
homework 5

An archer shoots an arrow. Consider the action force to be the bowstring against the arrow. The reaction to this force is the

A) combined weight of the arrow and bowstring.
B) air resistance against the bow.
C) friction of the ground against the archer’s feet.
D) grip of the archer’s hand on the bow.
E) arrow’s push against the bowstring.

E) arrow’s push against the bowstring.

test 1

Two people, one twice as massive as the other, attempt a tug-of-war with 12 meters of massless rope on frictionless ice. After a brief time, they meet. The heavier person slides a distance of

A) 3 m.
B) 4 m.
C) 6 m.
D) 0 m.

B) 4 m.

test 1
homework 5

A baseball player bats a ball with a force of 1000 N. The reaction force that the ball exerts against the bat is

A) less than 1000 N.
B) more than 1000 N.
C) 1000 N.
D) impossible to determine.

C) 1000 N.

test 1

A skydiver falls towards the Earth. The attraction of the Earth on the diver pulls the diver down. What is the reaction to this force?

A) air resistance the diver encounters while falling
B) water resistance that will soon act upward on the diver
C) the attraction to the planets, stars, and every particle in the universe
D) all of these
E) none of these

E) none of these

test 1

A 400 kg vehicle is travelling in outer space at a speed of 200 m/s. The smallest constant force that must be applied to stop it in 20 seconds is

A) 160 N.
B) 800 N.
C) 40 N.
D) 4000 N.

D) 4000 N.

test 1

A sheet of paper can be withdrawn from under a container of milk without toppling it if the paper is jerked quickly. This best demonstrates that

A) the milk carton has no acceleration.
B) there is an action-reaction pair of forces.
C) gravity tends to hold the milk carton secure.
D) the milk carton has inertia.
E) none of these

D) the milk carton has inertia.

Practice test 1

The gain in speed each second for a freely-falling object is about

A) 0
B) 10 m/s
C) 5 m/s
D) 20 m/s

B) 10 m/s

Practice test 1

A package falls off a truck that is moving at 30 m/s. Neglecting air resistance, the horizontal speed of the package just before it hits the ground is

A) zero.
B) less than 30 m/s but larger than zero.
D) more than 30 m/s.

Practice test 1

When a rocket ship accelerating in outer space runs out of fuel, it

A) accelerates for a short time, then slows down to a constant velocity.
B) accelerates for a short time, slows down, and eventually stops.
C) no longer accelerates.

C) no longer accelerates.

Practice test 1

If no external forces are acting on a moving object, it will

A) continue moving at the same speed.
B) continue moving at the same velocity.
C) move slower and slower until it finally stops.

B) continue moving at the same velocity.

Practice test 1

The last instant just before an airplane crashes a passenger jumps out the door and falls only two feet to the ground. The passenger

A) lucky to have studied physics
B) unharmed
C) probably hurt or killed
D) intelligent to think so fast

C) probably hurt or killed

practice test 1
homework 2

A horse gallops a distance of 10 kilometers in a time of 30 minutes. It’s average speed is

A) 20 km/h
B) 15 km/h
C) 30 km/h
D) 40 km/h

A) 20 km/h

Practice test 1

While an object near the Earth’s surface is in free fall, its

A) velocity increases.
B) acceleration increases.
C) mass increases.
D) mass decreases.

A) velocity increases.

Practice test 1

If an object moves with constant acceleration, its velocity must

A) be constant also.
B) change by the same amount each second.
C) change by varying amounts depending on its speed.
D) always decrease.

B) change by the same amount each second.

Practice test 1
homework 3

The two measurements necessary for calculating average speed are

A) acceleration and time.
B) velocity and time.
C) distance and time.
D) distance and acceleration.
E) velocity and distance.

C) distance and time.

Practice test 1

A heavy object and a light object are dropped at the same time from rest in a vacum. The heavier object reaches the ground

A) later than the lighter object
B) sooner than the lighter object
C) at the same time as the lighter object
D) almost immediately

C) at the same time as the lighter object

Practice test 1

If a rocket initially at rest accelerates at a rate of 50 m/s^2 for one minute, its speed will be

A) 3600 m/s
B) 50 m/s
C) 500 m/s
D) 3000 m/s

D) 3000 m/s

50 m/s^2 * 60

Practice test 1

A ball tossed vertically upwards rises, reaches its highest point, and then falls back to its starting point. During this time the acceleration of the ball is always

A) opposite its velocity
B) directed upwards
C) directed downwards
D) in the direction of motion

C) directed downwards

Practice test 1
homework 3

An object covers a distance of 8 meters in the first second of travel, another 8 meters during the next second, and 8 meters again during the third second. Its acceleration in meters per second per second is approximately

A) 0.
B) 5.
C) 8.
D) 24.

A) 0.

Practice test 1

At one instant a heavy object in air is moving upward at 50 meters per second. One second later its speed is approximately

A) 40 m/s.
B) 50 m/s.
C) 55 m/s.
D) 60 m/s.

A) 40 m/s.

Practice test 1

Disregarding air resistance, objects fall with constant

A) velocity.
B) speed.
C) acceleration.
D) distances each successive second.

C) acceleration.

Practice test 1

A car accelerates at 2 meters per second per second. Assuming the car starts from rest, how much time does it need to accelerate to a speed of 30 m/s?
A) 2 seconds
B) 15 seconds
C) 30 seconds
D) 60 seconds
E) none of these
B) 15 seconds

Practice test 1

A bullet is dropped from the top of the Empire State Building while another bullet is fired downward from the same location. Neglecting air resistance, the acceleration of

A) the fired bullet is greater.
B) the dropped bullet is greater.
C) each bullet is 10 meters per second per second.

C) each bullet is 10 meters per second per second.

Practice test 1

A ball is thrown upwards. Neglecting air resistance, what initial upward speed does the ball need to remain in the air for a total time of 10 seconds?

Practice test 1

An object maintains a constant acceleration unless there is a change in

A) its mass
B) the air resistance
C) the applied force
D) any of the above

D) any of the above

Practice test 1

If one object has twice as much mass as another object, it also has twice as much

A) inertia.
B) velocity.
C) acceleration due to gravity.
D) volume.
E) all of these

A) inertia.

Practice test 1

Strange as it may seem, it is just as hard to accelerate a car on a level surface on the moon as it is here on the Earth. This is because

A) the mass of the car is independent of gravity.
B) the weight of the car is independent of gravity.
C) Nonsense! A car is much more easily accelerated on the moon than on the Earth.

A) the mass of the car is independent of gravity.

Practice test 1

The Newtone is a unit of

A) density
B) mass
C) inertia
D) force

D) force

Practice test 1

An object is propelled along a straight-line path by a force. If the net force were doubled, the object’s acceleration would be

A) half as much.
B) the same.
C) twice as much.
D) four times as much.
E) none of these

C) twice as much.

Practice test 1

The force of friction on a sliding object is 10 newtons. The applied force needed to maintain a constant velocity is

A) more than 10 N.
B) less than 10 N.
C) 10 N.

C) 10 N.

Practice test 1

A 10-N falling object encounters 4 N of air resistance. The net force on the object is

A) 0 N.
B) 4 N.
C) 6 N.
D) 10 N.
E) none of these

C) 6 N.

Practice test 1
homework 4

An apple at rest weighs 1 N. The net force on the apple when it is in free fall is

A) 0 N.
B) 0.1 N.
C) 1 N.
D) 9.8 N.
E) none of these

C) 1 N.

Practice test 1

A girl pulls on a 10-kg wagon with a constant horizontal force of 30 N. If there are no other horizontal forces, what is the wagon’s acceleration in meters per second per second?

A) 0.3
B) 3.0
C) 10
D) 30
E) 300

B) 3.0

Practice test 1
homework 4

The mass of a pet turtle that weighs 10 N is

E) none of these

Practice test 1

An object following a straight-line path at constant speed

A) has a net force acting upon it in the direction of motion.
B) has zero acceleration.
C) has no forces acting on it.
D) none of these

B) has zero acceleration.

Practice test 1

Neglecting friction, a large block of ice and a small block of ice start sliding down an incline together. The heavier block will get to the bottom

A) before the light block.
B) after the light block.
C) at the same time as the light block.

C) at the same time as the light block.

Practice test 1

A rock is thrown vertically into the air. At the very top of its trajectory the net force on it is

A) less than its weight.
B) more than its weight.
C) equal to its weight.

C) equal to its weight.

Practice test 1

A jumbo jet has a mass of 100,000 kg. The thrust for each of its four engines is 50,000 N. What is the jet’s acceleration in meters per second per second when taking off?

A) 0.25
B) 1
C) 2
D) 4
E) none of these

C) 2

Practice test 1

A car traveling at 22 m/s comes to an abrupt halt in 0.1 second when it hits a tree. What is the deceleration in meters per second per second of the car?

A) 110
B) 220
C) 800
D) 880
E) can’t be solved without the mass of the car

B) 220

Practice test 1

A 2000-kg car experiences a braking force of 10,000 N and skids to a stop in 6 seconds. The speed of the car just before the brakes were applied was

A) 1.2 m/s.
B) 15 m/s.
C) 30 m/s.
D) 45 m/s.
E) none of these

C) 30 m/s.

Practice test 1

When a falling object has reached its terminal velocity, its acceleration is

A) constant.
B) zero.
C) g.

B) zero.

Practice test 1
homework 4

A skydiver jumps from a high-flying plane. As her velocity of fall increases, her acceleration

A) increases.
B) decreases.
C) remains unchanged regardless of air resistance.

B) decreases.

Practice test 1

A skydiver’s terminal velocity will be greatest if she falls

B) lying flat on her back.
C) lying flat on her stomach.
D) with her parachute open.

Practice test 1
homework 4

A large and a small person wish to parachute at equal terminal velocities. The larger person will have to

A) jump first from the plane.
B) get a larger parachute.
C) pull upward on the supporting strands to decrease the downward net force.
D) jump lightly.

B) get a larger parachute.

Practice test 1

A player catches a ball. Consider the action force to be the impact of the ball against the player’s glove. The reaction to this force is the

A) player’s grip on the glove.
B) force the glove exerts on the ball.
C) friction of the ground against the player’s shoes.
D) muscular effort in the player’s arms.
E) none of these

B) force the glove exerts on the ball.

Practice test 1
homework 5

As a ball falls, the action force is the pull of Earth on the ball. The reaction force is the

A) air resistance acting against the ball.
B) acceleration of the ball.
C) pull of the ball’s mass on the Earth.
D) none of these

C) pull of the ball’s mass on the Earth.

Practice test 1

Earth pulls on the moon. Similarly the moon pulls on Earth, evidence that

A) these two pulls comprise an action-reaction pair.
B) Earth is larger so its pull is larger.
C) the moon is smaller so its pull is smaller.
D) larger objects pull harder.

A) these two pulls comprise an action-reaction pair.

Practice test 1
homework 5

Joe pushes Bill, who is asleep. Bill

A) does not push even after he wakes up
B) pushes Joe equally hard even without waking up
C) will ineviable push Joe when he wakes up
D) push Joe immediately, but not as hard

B) pushes Joe equally hard even without waking up

Practice test 1
homework 5

A horse exerts 500N of force on a heavy wagon. The wagon pulls back on the horse with an equal force. The wagon still accelerates because

A) these forces are not an action-reaction pair
B) nevertheless there is still an unbalance force on the wagon
C) the horse pulls on the wagon a brief time before the wagon reacts
D) the wagon doesn’t accelerate because these forces are equal and opposite.

B) nevertheless there is still an unbalance force on the wagon

Practice test 1
homeowrk

A vehicle that weights 400 N on the surface of the Earth is traveling in outer space at a speed of 400 m/s . It can be stopped by applying a constant force of 20 N for

A) 2 seconds.
B) 4 seconds.
C) 80 seconds.
D) 400 seconds.
E) 800 seconds.

E) 800 seconds.

Practice test 1

A car traveling at 100 km/hr strikes an unfortunate bug and splatters it. The force of impact is

A) greater on the bug.
B) greater on the car.
C) the same for both.

C) the same for both.

Practice test 1

As an object falls

A) its velocity increases
B) its acceleration increases

A) its velocity increases

homework 2

When you yank a table cloth out from under your dishes you are demonstrating

A) impulse
B) inertia
C) gravity
D) momentum

B) inertia

homework 2

What is the acceleration of a freely falling object

A) 10m/s^2
B) 0m/s^2
C) 5m/s^2

A) 10m/s^2

homework 2

A package falls out of an airplane that is traveling at 300m/s. Neglecting air resistance, what is its horizontal velocity before hitting the ground?

A) greater than 300m/s
A package falls out of an airplane that is traveling at 300m/s. Neglecting air resistance, what is its horizontal velocity before hitting the ground?
A) greater than 300m/s
B) equal to 300m/s
C) less than 300m/s

C) less than 300m/s

homework 2

A disco ball falls from the midpoint of the ceiling of a moving van. It lands

A) at a point in front of the midpoint
B) at a point behind the midpoint
C) directly below the midpoint

C) directly below the midpoint

homework 2

If you run out of gas while driving you don’t come to a sudden stop. Why?

A) inertia
B) gravity
C) weight
D) terminal velocity

A) inertia

homework 2

According to Newton’s laws a train in motion would continue moving with its engines off. Why don’t we observe this

A) government conspiracy
B) gravity
C) friction
D) impulse

C) friction

homework 2

A moving object must have a change of

A) heart
B) position
C) direction
D) momentum

B) position

homework 2

If a spaceship accelerating in outer space runs out of fuel it

A) continues to accelerate
B) no longer accelerates
C) slows to a stop

B) no longer accelerates

homework 2

If no external forces act on an object it will

A) continue moving with the same speed
B) continue moving with the same velocity

B) continue moving with the same velocity

homework 2

Galileo used an inclined plane to effectively

A) eliminate friction
B) increase the acceleration beyond that of free fall
C) slow down the acceleration of gravity

C) slow down the acceleration of gravity

homework 3

A car maintains a velocity of 45km/hr for 15 seconds, its acceleration is

A) 0.333m/s^2
B) 60m/s^2
C) 3m/s^2
D) 0m/s^2

D) 0m/s^2

homework 3

8 seconds after falling from rest the speed of a rock is

A) impossible to determine
B) 4m/s^2
C) 80m/s
D) 320m

C) 80m/s

homework 3

At one instant a ball is falling at 40m/s, after one second it is falling at

A) 40
B) 30
C) 50
D) 60

C) 50

homework 3

Each second that an object falls the distance it covers is

A) increasing
B) constant, but not 5m or 10m
C) 5m
D) 10m

A) increasing

homework 3

A ball is thrown up at 35m/s, to get to the highest point takes

A) 7s
B) 125m
C) 3.5s

C) 3.5s

homework 3

Which has the greater mass?

A) an automobile battery
B) a king-size pillow
C) neither – both have the same

A) an automobile battery

homework 4

A ball is thrown vertically into the air. Because of air resistance, its speed when it returns to its starting level compared with its initial speed is

A) the same
B) more
C) less

C) less

homework 5

The attraction of a person’s body toward the Earth is called weight. The reaction to this force is

A) the Earth’s surface pushing against the person’s body
B) the person’s body pulling on the Earth

B) the person’s body pulling on the Earth

homework 5

A automobile and a baby carriage traveling at the same speed collide head-on. The impact force is

A) the same for both
B) greater on the automobile
C) greater on the baby carriage

A) the same for both

homework 5

A Mack truck and a Volkswagen have a head-on collision. The vehicle that undergoes the greatest change in velocity will be the

A) Volkswagen
B) same for both
C) Mack truck

A) Volkswagen

homework 5

A karate chop delivers a blow of 3000 N to a board that breaks. The force that acts on the hand during this event is

A) 3000N
B) zero
C) 6000N
D) 1500N

A) 3000N

homework 5

A piece of rope is pulled by two people in a tug-of-war. Each pulls with 400 N of force. What is the tension in the rope?

A) 800N
B) zero
C) 600N
D) 400N

D) 400N

homework 5

A 40kg vehicle is traveling in outer space at a speed of 30 m/s . It can be stopped by applying a constant force of 200 N for

A) 24s
B) 180m
C) 15m/s
D) 6s

D) 6s

homework 5

Practice Test 6-8
If the polar icecaps melted, the resulting water would spread over the entire Earth. This new mass distribution would tend to make the length of a day

A) longer.
B) shorter.
C) stay the same.
D) shorter at first, then longer.
E) longer at first, then shorter

A) longer.

Practice Test 6-8

A huge rotating cloud of particles in space gravitate together to form an increasingly dense ball. As it shrinks in size, the cloud

A) rotates faster.
B) rotates slower.
C) rotates at the same speed.
D) cannot rotate.

A) rotates faster.

Practice Test 6-8

If the Earth rotated more slowly about its axis, your apparent weight would

A) increase.
B) decrease.
C) stay the same.
D) be zero.

A) Increase.

Practice Test 6-8

To kick a football so it won’t topple end over end, kick it so the force of impact extends

A) above its center of gravity.
B) through its center of gravity.
C) below its center of gravity.

B) through its center of gravity.

Practice Test 6-8

A tightrope walker more easily balances on a tightwire if his pole

A) is held high.
B) droops.
C) is short but heavy.

B) droops.
The long, heavy tail of a spider monkey enables the monkey to easily vary its

A) weight.
B) momentum.
C) inertia.
D) center of gravity.
E) none of these

D) center of gravity.

Practice Test 6-8

The famous Leaning Tower of Pisa doesn’t topple over because its center of gravity is

A) above a place of support.
B) relatively low for such a tall building.
C) stabilized by its structure.
D) displaced from its center.
E) in the same place as its center of mass.

A) above a place of support.

Practice Test 6-8

Two identical objects in outer space have a head-on collision and stick together. If, before the collision, one had been moving at 2 m/s and the other at 1 m/s, their combined speed after the collision would be

A) 0.5 m/s.
B) 0.33 m/s.
C) 0.67 m/s.
D) 1.0 m/s.
E) none of these

A) 0.5 m/s.

Practice Test 6-8

Compared to the recoiling rifle, the bullet fired has

A) a greater momentum.
B) a greater kinetic energy.
C) a smaller speed.
D) all of the above

B) a greater kinetic energy.

Practice Test 6-8

An open freight car rolls friction free along a horizontal track in a pouring rain that falls vertically. As water accumulates in the car, the car’s speed

A) increases.
B) decreases.
C) doesn’t change.
D) cannot be determined with the information given

B) decreases.

Practice Test 6-8

A heavy and a light object released from the same height in a vacuum have equal

A) weights.
B) momenta.
C) kinetic energies.
D) accelerations.
E) none of the above

D) accelerations.

Practice Test 6-8

If an object has kinetic energy, then it also must have

A) impulse.
B) momentum.
C) acceleration.
D) force.
E) none of these

B) momentum.
A moving object has

A) speed.
B) velocity.
C) momentum.
D) energy.
E) all of these

E) all of these

Practice Test 6-8

Whereas impulse involves the time that a force acts, work involves the

A) distance that a force acts.
B) time and distance that a force acts.
C) acceleration that a force produces.

A) distance that a force acts.

Practice Test 6-8

A car’s engine is 20% efficient. When cruising, the car encounters an average retarding force of 1000 N. If the energy content of gasoline is 40 megajoules per liter, how many kilometers per liter does the car get?

A) 14
B) 12
C) 10
D) 8
E) none of these

D) 8

40,000,000/1000 = 40,000
40,000 m / 1000 = 40 km / L
40 * .20
8

Practice Test 6-8

How many Joules of energy are in one kilowatt-hour?

A) 1
B) 60
C) 60,000
D) 3.6 million
E) none of these

D) 3.6 million

1 joule = 1 Watt for 1 second.

60 seconds * 60 minutes = 3600 joules in watt-hour
3600 * 1000
3,600,000 joules in a kilowatt-hour

Practice Test 6-8

The ball rolling down an incline has its maximum potential energy at

A) the top.
B) a quarter of the way down.
C) halfway down.
D) the bottom.

A) the top.

Practice Test 6-8

An object may have potential energy because of its

A) speed.
B) acceleration.
C) momentum.
D) location.
E) none of these

D) location.

Practice Test 6-8

A 1000-kg car and a 2000-kg car are hoisted the same distance. Raising the more massive car requires

A) less work.
B) as much work.
C) twice as much work.
D) four times as much work.
E) more than four times as much work.

C) twice as much work.

Practice Test 6-8

If you push an object a given distance, while applying twice the force, you do

A) twice as much work.
B) four times as much work.
C) the same amount of work.
D) half as much work.

A) twice as much work.
If you push for a half hour or a whole hour against a stationary wall

A) no work on the wall is done in either case.
B) half as much work is done during the half hour.
C) twice as much work is done during the half hour.
D) it is impossible to determine how much work is done.

A) no work on the wall is done in either case.

Practice Test 6-8

If a monkey floating in outer space throws his hat away, the hat and the monkey will both

A) move away from each other, but at different speeds.
B) move away from each other at the same speed.
C) move a short distance and then slow down.
D) move a short distance and then go faster.
E) come to a stop after a few minutes.

A) move away from each other, but at different speeds.

Practice Test 6-8

Momentum is transferred to the ground when an apple falls on it. The momentum absorbed by the ground is

A) negligible compared to the momentum of the apple.
B) greater than that of the apple only if the apple bounces.
C) greater than that of the apple in all cases.
D) none of these

B) greater than that of the apple only if the apple bounces.

Practice Test 6-8

A 5-kg shark swimming at a speed of 1 m/s swallows an absent-minded 1-kg fish swimming toward it at 4 m/s. The speed of the shark after this meal is

A) 1/2 m/s.
B) 1/5 m/s.
C) 1/6 m/s.
D) 2/3 m/s.
E) 3/2 m/s.

C) 1/6 m/s.

Practice test 6-8
test 6-8

A rifle of mass 2 kg is suspended by strings. The rifle fires a bullet of mass 0.01 kg at a speed of 200 m/s. The recoil velocity of the rifle is about

A) 0.001 m/s.
B) 0.01 m/s.
C) 0.1 m/s.
D) 1 m/s.
E) none of these

D) 1 m/s.

m1v1 = m2v2

.01*200 = 2 * ?

.01*200/2
2/2 = 1

A large metal ball is shot from a cannon with a short barrel. If the same ball were to be shot from cannon with a longer barrel, its muzzle velocity would be

A) less.
B) more.
C) the same.
D) impossible to determine without additional information.

B) more.

Practice Test 6-8

A 1-kg chunk of putty moving at 1 m/s collides with and sticks to a 5-kg bowling ball initially at rest. The bowling ball and putty then move with a momentum of

A) 0 kg m/s.
B) 1 kg m/s.
C) 2 kg m/s.
D) 5 kg m/s.
E) more than 5 kg m/s.

B) 1 kg m/s

Practice Test 6-8

A karate expert executes a swift blow and breaks a cement block with her bare hand. The magnitude of the force experienced by her hand is

A) zero.
B) less than the force applied to the cement block.
C) identical to the force applied to the block.
D) more than the force applied to the block.
E) impossible to predict without additional information

C) identical to the force applied to the block.

Practice Test 6-8

A heavy truck and a small car rolling down a hill at the same speed are forced to stop in the same amount of time. Compared to the force that stops the car, the force needed to stop the truck is

A) greater.
B) smaller.
C) the same.

A) greater.

Practice Test 6-8

A ball is moving at 3 m/s and has a momentum of 48 kg m/s. What is the ball’s mass?

A) 4 kg
B) 12 kg
C) 16 kg
D) 144 kg
E) none of these

C) 16 kg

Practice Test 6-8

Padded dashboards in cars are safer in an accident than nonpadded ones because an occupant hitting the dash has

A) increased time of impact.
B) decreased time of impact.
C) decreased impulse.
D) increased momentum.

A) increased time of impact.

Practice Test 6-8

When you jump from an elevated position you usually bend your knees upon reaching the ground. By doing this, you make the time of the impact about 10 times as great as for a stiff-legged landing. In this way the average force your body experiences is

A) less than 1/10 as great.
B) more than 1/10 as great.
D) about 10 times as great.

Practice Test 6-8
Test 6-8

A large heavy truck and a small baby carriage roll down a hill. Neglecting friction, at the bottom of the hill, the baby carriage will have a greater

A) speed.
B) acceleration.
C) momentum.
D) all of these
E) none of these

E) none of these

Practice Test 6-8

The difference between impulse and impact force involves the

A) difference between acceleration and velocity
B) distance the force acts
C) mass and its effect on resisting a change in momentum
D) time the force acts

D) time the force acts

Homework 6
test 2

It is correct to say that impulse is equal to
A) velocity multiplied by time
B) momentum
C) the force multiplied by the distance the force acts
D) the change in momentum
D) the change in momentum

Homework 6
Practice Test 6-8

A rifle recoils while firing a bullet. The speed of the rifle’s recoil is small because the

A) force against the rifle is smaller than against the bullet
B) momentum of the rifle is smaller
C) rifle has much more mass than the bullet

C) rifle has much more mass than the bullet
Homework 6
Test 6-8
Suppose that a tiny gun made of a strong but very light material fires a bullet that is more massive than the gun itself. For such a weapon

A) conservation of momentum would not hold
B) the target would be safer than the shooter
C) recoil problems would be lessened

B) the target would be safer than the shooter

Homework 6
Practice Test 6-8

In order to catch a ball, a baseball player extends the hand forward before impact with the ball and then lets it ride backward in the direction of the ball’s motion .. Doing this reduces the force of impact on the player’s hand principally because the

A) time of impact is decreased
B) time of impact is increased
C) relative velocity is less

B) time of impact is increased

Homework 6
Test 6-8

A 4 kg ball has a momentum of 12 kg m/s. What is the ball’s speed?

A) 48 m/s
B) 4 m/s
C) 3 m/s
D) 12 m/s

C) 3 m/s

Homework 6
Test 6-8

Recoil is noticeable if we throw a heavy ball while standing on roller skates. If instead we go through the motions of throwing the ball but hold onto it, our net recoil will be

A) the same as before
B) small but noticeable
C) zero

C) zero

Homework 6
Test 6-8

The force that accelerates a rocket in outer space is exerted on the rocket by the

A) rocket’s wings
B) atmospheric pressure
C) rocket’s nose cone
D) exhaust gases

D) exhaust gases

Homework 6

Two billiard balls having the same mass and speed roll toward each other. What is their combined momentum after they meet?

A) twice the sum of their original momentums
B) half the sum of their original momentums
C) zero

C) zero
Because the are no external forces, total momentum is conserved. The inital momentum will equal the final momentum. Let m1 be the momentum of 1 and m2 the momentum of the other. Because they are rolling towards one other, the total momentum is

having the same mass and speed roll
m1 – m1 = 0

Homework 6
Practice Test 6-8

A 1000-kg car moving at 10 m/s brakes to a stop in 5 s. The average braking force is

A) 5000N
B) 4000N
C) 2000N
D) 3000N
E) 1000N

C) 2000N

=(1000*10)/5
=10,000/5
=2000

Homework 6
Practice Test 6-8

A 6-kg shark swimming at a speed of 8 m/s swallows an absent-minded 2-kg fish swimming 4 m/s in the opposite direction. The speed of the shark after this lunch is

A) 4 m/s
B) 3 m/s
C) 8 m/s
D) 5 m/s

D) 5 m/s

Add the momentums of the fish and then divide by the masses.

p=mv

[(m1*v1) + (m2*v2)]/(m1+m2)

[(6*8)+(2*-4)]/(6+2)

Homework 6

You’re driving down the highway and a bug spatters into your windshield. Which undergoes the greater change in momentum during the time of contact?

A) the bug
B) the car
C) both the same

C) both the same

Change in momentum is also known as “impulse”… and described by the equation Impulse = ΔFΔt, where F is force and t is time.

According to Newton’s laws, both the car and the bug experience the same force (F = ma, since the masses are so different, the acceleration will be also… and the force is always the same for both objects in a collision). They also both experienced the same change in time, as one part of the collision can’t have different Δt than another part. Since both change in force, and change in time are the same, so is the impulse, and therefore the change in momentum :]

Homework 6
test 6-8

If you push an object twice as far while applying the same force, you do

A) four times as much work.
B) twice as much work.
C) half as much work.
D) the same amount of work.

B) twice as much work.

Homework 7
Test 6-8

A job is done slowly, while an identical job is done quickly. Both jobs require the same amount of work, but different amounts of

A) energy
B) power
C) effort

B) power

Homework 7
Practice Test 6-8

If an object is raised twice as high, its potential energy will be

A) half as much
B) twice as much
C) the same
D) four times as much

B) twice as much

Homework 7

An object that has kinetic energy must be
in an elevated position

A) moving
B) falling
C) at rest

A) moving

Homework 7
Test 6-8

A bow is drawn so that it has 40 J of potential energy. When fired, the arrow will ideally have a kinetic energy that is

A) less than 40J
B) 40J
C) more than 40J

B) 40J

Homework 7
Test 6-8

When a car is braked to a stop, its kinetic energy is transformed to

A) heat
B) stopping energy
C) potential energy
D) energy of rest

A) heat

it changes to potential energy
in some cases yes it will convert back to potential energy… however in this cases when dealing with a car the brakes apply friction which causes heat that eventually brings the car to a stop therefore when completely stopped the kinetic energy will be transformed into heat.

Homework 7
Practice Test 6-8

A block of ice sliding down an incline has its maximum speed at

A) the top
B) the same everywhere
C) the bottom

C) the bottom

Homework 7

No work is done by gravity on a bowling ball that rolls along a bowling alley because

A) no distance is covered by the ball.
B) no force acts on the ball.
C) the force on the ball is at right angles to the ball’s motion.

C) the force on the ball is at right angles to the ball’s motion.

‘Work’ is only done by a force if the speed of an object changes because of that force.

a. is a filler answer to make up the number of 4.
b. nice but incorrect. Gravity and repulsion (from the floor) both act on the ball but they are in perfect balance. But you can’t say they don’t act.

Gravity is not changing the speed of the ball because it is not acting in the direction of it’s motion.

work is dependant on displacement.
there is no dispacement in the y direction. ( The ball only moves in the x direction) Therefore no work is done by gravity.

Homework 7
Practice Test 6-8

A TV set is pushed a distance of 2 m with a force of 20 N. How much work is done on the set?

A) 40J
B) 18J
C) 10J
D) 400J

A) 40J

W = Fd
Work = Force x displacement

Homework 7

A car that travels twice as fast as another when braking to a stop will skid

A) the same distance
B) four times as far
C) twice as far

C) twice as far

Homework 7
Test 6-8

If an object has kinetic energy, then it also must also have

A) impulse
B) acceleration
C) force
D) momentum

D) momentum

Homework 7
Practice Test 6-8

A bullet has more kinetic energy than the recoiling rifle from which it is fired is because the force on the bullet acts over a

A) longer time
B) longer distance

B) longer distance

Homework 7
Test 6-8

Horses that move with the fastest linear speed on a merry-go-round are located

A) near the outside
B) near the center
C) they all move at the same speed

A) near the outside

Homework 8
Practice Test 6-8

If you replace the wheels and tires of your car with new ones having greater diameters, all of your speedometer readings thereafter will

A) decrease
B) remain the same
C) increase

A) decrease

Homework 8
Practice Test 6-8

When a train makes a curve, the wheels squeal because different parts of the wheel rims

A) must all contract at the same time.
B) try to cover a different distance in the same time.
C) vibrate at different rates.

B) try to cover a different distance in the same time.

Homework 8
Practice Test 6-8

Suppose the circumference of a bicycle wheel is 2 meters. If it rotates at 1 revolution per second when you are riding the bicycle, then your speed will be

A) 3 m/s
B) 1 m/s
C) 3.14 m/s
D) 2 m/s

D) 2 m/s

Homework 8
Practice Test 6-8

An industrial flywheel has a greater rotational inertia when most of its mass is

A) uniformly distributed
B) near the center
C) near the outer edge

C) near the outer edge

Homework 8
Test 6-8

A coin and a ring roll down an incline starting at the same time. The one to reach the bottom first will be the

A) ring
B) both reach at the same time
C) coin

C) coin

Homework 8
Practice Test 6-8

On a balanced see saw, a boy three times as heavy as his partner sits

A) 1/9 the distance from the fulcrum.
B) three times the distance from the fulcrum.
C) 1/3 the distance from the fulcrum.
D) nine times the distance from the fulcrum.

C) 1/3 the distance from the fulcrum.

Homework 8
Test 6-8

Put a pipe over the end of a wrench when trying to turn a stubborn nut on a bolt, to effectively make the wrench handle twice as long, you’ll multiply the torque by

A) four
B) two
C) six
D) eight

B) two

Homework 8
Practice Test 6-8

Toss a baseball bat into the air and it wobbles about its

A) heavier end
B) center of mass
C) geometrical center

B) center of mass

Homework 8
Test 6-8

The chef at the infamous Fattening Tower of Pizza tosses a spinning disk of uncooked pizza dough into the air. The disk’s diameter increases during the flight, while its rotational speed

A) increases
B) decreases
C) remains the same

B) decreases

Homework 8
Test 6-8

For a system in mechanical equilibrium,

A) the forces equal the torques.
B) the net forces and torques must both be zero.
C) acceleration is negative

B) the net forces and torques must both be zero.

Homework 8

Suppose you’re on a Ferris wheel at a carnival, seated 15 m from the Ferris wheel’s axis. If you make a complete rotation each minute, your linear speed is

A) 3.14 m/s
B) 1.57 m/s
C) 15 m/s
D) .25 m/s

B) 1.57 m/s

one turn is a distance of 2piR = 2pi*15 m
the time needed for 1 turn is 1 min = 60 s
use v = s/t for the velocity
v = 2pi*15/60 = 1.57 m/s

Homework 8

A rifle of mass 2 kg is suspended by strings. The rifle fires a bullet of mass 0.01 kg at a speed of 200 m/s. The recoil velocity of the rifle is about

A) 0.001 m/s.
B) 0.01 m/s.
C) 0.1 m/s.
D) 1 m/s.
E) none of these

D) 1 m/s.

m1 = 2 kg
v1 = ?
m2 = 0.01 kg
v2 = 200 m/s

Set it up as a conservation of momentum problem

m1v1 = m2v2

Insert values and solve for v1

(2 kg) * v1 = (0.01 kg) * (200 m/s)
(2 kg) * v1 = (2 kg-m/s)
v1 = (2 kg-m/s) / (2 kg)
v1 = 1 m/s

Practice Test 6-8

Which of the following has the largest momentum relative to the Earth’s surface?

A) a tightrope walker crossing Niagara Falls
B) a pickup truck speeding along a highway
C) a Mack truck parked in a parking lot
D) the Science building on campus
E) a dog running down the street

B) a pickup truck speeding along a highway

Practice Test 6-8
Practice Test 6-8

Inside a freely-falling runaway elevator, your

A) acceleration is zero
B) gravitational interaction with earth is zero
C) normal force is zero
D) all of these
E) none of these

C) Normal force is zero

Practice Test 6-8

What prevents satelites such as a space shuttle from falling
A) gravity
B) the absence of air drag
C) nothing they are always falling continuously all around the earth
C) nothing they are always falling continuously all around the earth

Practice Test 6-8

An Earth satellite is in an elliptical orbit. The satellite travels fastest when it is

A) nearest the earth
B) farthest from the eart
C) it travels at a constant speed everywhere in orbit

A) nearest the earth

Practice test 6-8

A bullet is fired from a gun. The speed of the bullet will be about the same as the speed of the recoiling gun

A) because momentum is conserved.
B) because velocity is conserved.
C) because both velocity and momentum are conserved.
D) if the mass of the bullet equals the mass of the gun.
E) none of these

D) if the mass of the bullet equals the mass of the gun.

test 6-8

An astronaut , floating alone in outer space, throws a baseball. If the ball floats away at a speed of 20 meters per second, the astronaut will

A) move in the opposite direction at a speed of 20 m/s.
B) move in the opposite direction, but at a lower speed.
C) move in the opposite direction but at a higher speed.
D) not move as stated in any of the above choices.

B) move in the opposite direction, but at a lower speed.

Test 6-8

A golf ball moving forward with 1 unit of momentum strikes and bounces backward off a heavy bowling ball that is initially at rest and free to move. The bowling ball is set in motion with a momentum of

A) less than 1 unit.
B) more than 1 unit.
C) 1 unit.
D) not enough information

B) more than 1 unit.

Test 6-8

A 1-kg glider and a 2-kg glider both slide toward each other at 1 m/s on an air track. They collide and stick. The combined mass moves at

A) 0 m/s.
B) 1/2 m/s.
C) 1/3 m/s.
D) 1/6 m/s.
E) 1.5 m/s.

C) 1/3 m/s.

Test 6-8

A 5000-kg freight car runs into a 10,000-kg freight car at rest. They couple upon collision and move with a speed of 2 m/s. What was the initial speed of the 5000-kg car?

A) 4 m/s
B) 5 m/s
C) 6 m/s
D) 8 m/s
E) none of these

C) 6 m/s

Test 6-8

The change in momentum, in kg m/s, that occurs when a 1.0 kg ball travelling at 4.0 m/s strikes a wall and bounces back at 2.0 m/s is
A) 2.
B) 4.
C) 6.
D) 8.
C) 6.

Test 6-8

If you do work on an object in one-third the usual time, your power output is

A) one third the usual power output.
B) the usual power output.
C) three times the usual power output.
D) impossible to predict without additional information.

C) three times the usual power output.

Test 6-8

Do 100 J of work in 50 s and your power output is

A) 1/2 W
B) 2 W.
C) 4 W.
D) 50 W.
E) 5,000 W.

B) 2 W.

Test 6-8

An object lifted 10 meters gains 200 J of potential energy. If the same object is lifted 20 meters, its potential energy gain is

A) half as much.
B) the same.
C) twice as much.
D) four times as much.
E) more than four times as much.

C) twice as much.

Test 6-8

A pulley is capable of increasing energy.

A) sometimes true
B) always false
C) always true
D) sometimes false

B) always false

Test 6-8

When bullets are fired from an airplane in the forward direction, the momentum of the airplane will be

A) decreased.
B) unchanged.
C) increased.

A) decreased.

Test 6-8

After rolling halfway down an incline, a marble’s kinetic energy is

A) less than its potential energy.
B) greater than its potential energy.
C) the same as its potential energy.
D) impossible to determine.

C) the same as its potential energy.

Test 6-8

A ball rolling down an incline has its maximum kinetic energy at

A) the top.
B) halfway down.
C) three-quarters of the way down.
D) the bottom.

D) the bottom.

Test 6-8

What task requires the most work; lifting a 50-kg sack 2 meters or lifting a 25-kg sack 4 meters?

A) the 50-kg sack
B) the 25-kg sack
C) Both require the same amount of work.
D) impossible to determine without knowing the contents of the sack

C) Both require the same amount of work.

Test 6-8

A 2-kg mass is held 4 m above the ground. What is the approximate potential energy of the mass with respect to the ground?

A) 6 J
B) 8 J
C) 32 J
D) 80 J

D) 80 J

Test 6-8

Using 1000 J of work, a toy elevator is raised from the ground floor to the second floor in 20 seconds. The power needed to do this job was

A) 20 W.
B) 50 W.
C) 100 W.
D) 1000 W.
E) 20,000 W.

B) 50 W.

Test 6-8

A car moves 4 times as fast as another identical car. Compared to the slower car, the faster car has

A) 4 times the KE.
B) 8 times the KE.
C) 12 times the KE.
D) 16 times the KE.

D) 16 times the KE.

Test 6-8

A jack system will increase the potential energy of a heavy load by 1000 J with a work input of 2000 J. The efficiency of the jack system is

A) 10%.
B) 20%.
C) 50%.
D) 80%.

C) 50%.

Test 6-8

When a rifle is fired, it recoils as the bullet is set in motion. The rifle and bullet ideally acquire equal

A) but opposite amounts of momentum.
B) amounts of kinetic energy.
C) both of these
D) neither of these

A) but opposite amounts of momentum.

Test 6-8

A torque acting on an object tends to produce

A) equilibrium.
B) rotation.
C) linear motion.
D) velocity.
E) a center of gravity.

B) rotation.

Test 6-8

If the speed of a moving object doubles, which of the following also doubles?
A) momentum
B) kinetic energy
C) acceleration
D) all of the above
A) momentum

Test 6-8

A feather and a coin dropped in a vacuum fall with equal

A) forces.
B) momenta.
C) accelerations.
D) kinetic energies.
E) none of these

C) accelerations.

Test 6-8

Two pool balls, each moving at 2 m/s, roll toward each other and collide. Suppose after bouncing apart, each moves at 4 m/s. This collision violates conservation of

A) momentum.
B) energy.
C) both momentum and energy.
D) none of the above choices

B) energy.

Test 6-8

Two 5000-kg passenger cars roll without friction (one at 1 m/s, the other at 2 m/s) toward each other on a level track. They collide, couple, and roll away together with a combined momentum of

A) zero.
B) 5000 kg m/s.
C) 10,000 kg m/s.
D) 15,000 kg m/s.

B) 5000 kg m/s.

Test 6-8

If a record player’s rotational speed is doubled, then the linear speed of a pet hamster sitting on the edge of the record will

A) double.
B) halve.
C) remain the same.

A) double.

Test 6-8

Consider a string with several rocks tied along its length at equally spaced intervals. You whirl the string overhead so that the rocks follow circular paths. Compared to a rock in the middle of the string, a rock at the outer end moves

A) half as fast.
B) twice as fast.
C) at the same linear speed.

B) twice as fast.

Test 6-8

The center of mass of a human body is located at a point
A) that is fixed, but different for different people.
B) that is always directly behind the belly button.
C) that changes as a person bends over.
D) none of these
C) that changes as a person bends over.

Test 6-8

Two people are balanced on a seesaw. If one person leans toward the center of the seesaw, that person’s end of the seesaw will

A) rise.
B) fall.
C) stay at the same level.
D) rise and then fall.
E) fall and then rise.

A) rise.

Test 6-8

A car travels in a circle with constant speed. The net force on the car is

A) directed forward, in the direction of travel.
B) directed toward the center of the curve.
C) zero because the car is not accelerating.
D) none of these

B) directed toward the center of the curve.

Test 6-8

When a twirling ice skater brings her arms inward, her rotational speed

A) increases.
B) decreases.
C) remains the same.

A) increases.

Test 6-8

If the planet Jupiter underwent gravitational collapse, its rate of rotation about its axis would

A) decrease.
B) increase.
C) stay the same.

B) increase.

Test 6-8

Our Moon travels fastest as it orbits the Earth when it is

A) revolving
B) rotating
C) performing an eclipse
D) closest
E) All of the above choices are true

D) closest

Test 6-8

How many different elements are in a water molecule?

A) one
B) two
C) three
D) four

B) two

Homework 11
Test 11-14

Which of the following are electrically neutral?

A) proton
B) neutron
C) electron
D) ion
E) none of these

B) neutron

Homework 11
Practice test 11 – 14
test 11 – 14

What makes an element distinct?

A) the number of protons
B) the number of neutrons
C) the number of electrons
D) the total mass of all the particles
E) none of these

A) the number of protons

Homework 11
Practice test 11-14

Atoms heavier than hydrogen were made by

A) photosynthesis.
C) nuclear fusion.

C) nuclear fusion.

Homework 11

Which of these atoms has the most mass?

A) hydrogen
B) iron
D) uranium

D) uranium

Homework 11

In an electrically neutral atom, the number of protons in the nucleus is balanced by an equal number of
A) neutrons.
B) quarks.
C) orbital electrons.
C) orbital electrons.

Homework 11
Practice test 11-14

The lightest particle of those listed below is

A) a proton.
B) a molecule.
C) an electron.
D) an atom.

C) an electron.

Homework 11
Practice test 11-14

A force that determines the chemical properties of an atom is a(n)

A) friction force.
B) nuclear force.
C) gravitational force.
D) electrical force.

D) electrical force.

Homework 11
Practice Test 11-14

The air in this room has

A) mass.
B) weight.
C) energy.
D) all of these
E) none of these

D) all of these

Homework 11
Test 11-14

A factor that usually determines whether a substance is in the solid, liquid, gaseous, or plasma state is its

A) atomic shell configuration.
B) atomic number.
C) composition.
D) temperature.

D) temperature.

Homework 11

When a chocolate bar is cut in half, its density is

A) halved.
B) unchanged.
C) doubled.

B) unchanged.

Homework 12
Practice Test 11-14

Compared to the density of a kilogram of feathers, the density of a kilogram of lead is
A) less.
B) more.
C) the same.
B) more.

Homework 12
Practice Test 11-14

Which has the greater density, a lake full of water or a cup full of lake water?
A) the cup full of lake water
B) the lake full of lake water
C) Both have the same density.
C) Both have the same density.

Homework 12

You wish to bolt a sign to a horizontal I-beam supporting a bridge. You will weaken the beam least if you drill the bolt-holes through the

A) upper flange.
B) lower flange.
C) web.
D) All these will have the same effect.

C) web.

Homework 12
Practice test 11-14

Compared to the volume of a kilogram of feathers, the volume of a kilogram of lead is

A) less.
B) more.
C) the same.

A) less.

Homework 12

Stone slabs are stronger under

A) tension.
B) compression.
C) both tension and compression.

B) compression.

Homework 12
Test 11-14

A wooden block has a mass of 1000 kg and a volume of 2 cubic meters. What is the block’s density?

A) 100 kg per cubic meter
B) 200 kg per cubic meter
C) 500 kg per cubic meter
D) 1000 kg per cubic meter

C) 500 kg per cubic meter

Homework 12
Practice Test 11-14

Which potatoes when peeled produce the most peelings?

A) 10 kg of large potatoes
B) 10 kg of small potatoes
C) They both produce the same amount.

B) 10 kg of small potatoes

Homework 12
Test 11-14

Tripling the linear size of an object multiplies its area by

A) 3 and its volume by 9.
B) 9 and its volume by 18.
C) 9 and its volume by 27.
D) 27 and its volume by 81.

C) 9 and its volume by 27.

Homework 12

If you make cupcakes and bake them as directed for a cake, you will find the cupcakes

A) overbaked.
B) underbaked.
C) properly baked.

A) overbaked.

Homework 12
Test 11-14

Water pressure is greatest against the

A) top of a submerged object.
B) bottom of a submerged object.
C) sides of a submerged object.
D) is the same against all surfaces

B) bottom of a submerged object.

Homework 13
Practice Test 11-14

One liter of water has a mass of

A) 1 kilogram.
B) 14.7 grams.
C) 500 grams.

A) 1 kilogram.

Homework 13
Practice Test 11-14

Pumice is a volcanic rock that floats. Its density is

A) less than the density of water.
B) equal to the density of water.
C) more than the density of water.

A) less than the density of water.

Homework 13
Practice Test 11-14

A completely submerged object always displaces its own

A) volume of fluid.
B) weight of fluid.
C) density of fluid.
D) all of these

A) volume of fluid.

Homework 13
Practice Test 11-14

Blood pressure is normally greater in your

A) ears.
B) feet.
C) same in each

B) feet.

Homework 13
Practice Test 11-14

The density of a submerged submarine is about the same as the density of

A) a crab.
B) iron.
C) a floating submarine.
D) water.
E) none of these

D) water.

Homework 13

An egg is placed at the bottom of a bowl filled with water. Salt is slowly added to the water until the egg rises and floats. From this experiment, one concludes

A) calcium in the egg shell is repelled by sodium chloride.
B) the density of salt water exceeds the density of egg.
C) buoyant force does not always act upward.
D) salt sinks to the bottom.

B) the density of salt water exceeds the density of egg.

Homework 13

Flatten a spherical meat ball into a hamburger and you increase its

A) both of these
B) surface area.
C) neither of these
D) volume.*
B) surface area.

Homework 13
Practice Test 11-14

A hydraulic press multiplies a force by 100. This multiplication is done at the expense of

A) energy, which is divided by 100.
B) the distance through which the force acts.
C) the time through which the force acts, which is multiplied by 100.
D) the mechanism providing the force.

B) the distance through which the force acts.

Homework 13

The pascal is a pressure unit equal to one

A) newton per square meter.
B) kilogram per square meter.
C) newton per square centimeter.
D) kilogram per square centimeter.
E) square meter per newton.

A) newton per square meter.

Homework 13
Practice Test 11-14

A plasma differs from a gas in that

A) its molecules are farther apart.
B) it is hotter than a gas.
C) it is electrically conducting.
D) its atoms are boosted to higher atomic numbers.

C) it is electrically conducting.

Homework 14
Test 11-14

A balloon is buoyed up with a force equal to the

A) weight of air it displaces.
B) density of surrounding air.
C) atmospheric pressure.
D) weight of the balloon and contents.

A) weight of air it displaces.

Homework 14
Practice Test 11-14

As a helium-filled balloon rises in the air, it becomes

A) bigger.
B) more dense.
C) heavier.
D) all of these

A) bigger.

Homework 14
Test 11-14

In drinking soda or water through a straw, we make use of

A) capillary action.
B) surface tension.
C) atmospheric pressure.
D) Bernoulli’s principle.

C) atmospheric pressure.

Homework 14
Practice Test 11-14
Test 11-14

The faster a fluid moves, the

A) greater its internal pressure.
B) less its internal pressure.
C) internal pressure is unaffected.

B) less its internal pressure.

Homework 14
Practice Test 11-14

A suction cup sticks to a wall. It is

A) pulled to the wall by the vacuum.
B) pushed to the wall by the atmosphere.
C) both of these
D) neither of these

B) pushed to the wall by the atmosphere.

Homework 14
Practice Test 11-14
Test 11-14

Alcohol is less dense than water. If alcohol is used to make a barometer on a day when atmospheric pressure is normal, the height of the alcohol column would be

A) less than 10.3 m.
B) more than 10.3 m.
C) 10.3 m.

B) more than 10.3 m.

Homework 14
Practice Test 11-14

In a vacuum, an object has no

A) buoyant force.
B) mass.
C) weight.
D) temperature.

A) buoyant force.

Homework 14
Practice Test 11-14

In a vacuum a marshmallow becomes

A) larger.
B) smaller.
C) flat.
D) a hollow shell.

A) larger.

Homework 14

When a common fluorescent lamp is on, the mercury vapor inside is actually in a

A) gaseous state.
B) liquid state.
C) plasma state.
D) solid state.

C) plasma state.

Homework 14

Which of these statements is true?

A) A molecule is the smallest particle that exists.
C) Molecules form atoms that in turn determine chemical properties of a substance.
D) Molecules are the smallest subdivision of matter that still retains chemical properties of a substance.
E) None of these statements is true.

D) Molecules are the smallest subdivision of matter that still retains chemical properties of a substance.

Practice Test 11-14
Test 11-14

A molecule has

A) Structure
B) mass.
C) energy.
D) all of these

D) all of these

Practice Test 11-14

If an astronaut landed on a planet made of antimatter, there would be an explosion and

A) the planet would annihilate.
B) an amount of planet matter equal to that of the astronaut would annihilate.
C) the astronaut would annihilate.
D) the astronaut and an equal amount of the planet would both annihilate.

D) the astronaut and an equal amount of the planet would both annihilate.

Practice Test 11-14

In our part of the universe, antimatter is

A) non-existent.
B) plentiful.
C) short-lived.
D) long-lived.

C) short-lived.

Practice Test 11-14

Nuclei of atoms that make up a newborn baby were made in

A) the mother’s womb.
B) the food the mother eats before giving birth.
C) ancient stars.
D) the Earth.
E) none of these.

C) ancient stars.

Practice Test 11-14

If one neutron is added to a helium nucleus, the result is

A) hydrogen.
B) boron.
C) lithium.
D) beryllium.
E) helium.

E) helium.

Practice Test 11-14

The reason a granite block is mostly empty space is that the atoms in the granite are

A) in perpetual motion.
B) mostly empty space themselves.
C) held together by electrical forces.
D) not as close together as they could be.
E) invisible.

B) mostly empty space themselves.

Practice Test 11-14

If the mass of an object were to double while its volume remains the same, its density would

A) halve.
B) double.
C) stay the same.
D) become four times as great.

B) double.

Practice test 11-14

When weight is applied to the top of a stone arch, all of the stone blocks in the arch undergo

A) tension.
B) compression.
C) expansion.
D) change of phase.

B) compression.

Practice test 11-14

The strength of a rope depends on its

A) thickness.
B) length.
C) both of these.

A) thickness.

Practice test 11-14

An iron block is placed in a furnace where it is heated and consequently expands. In the expanded condition, its density

A) is less.
B) is the same.
C) is more.

A) is less.

Practice test 11-14

An unstretched hanging spring is 50 cm long. Suspending a 100-N weight from it makes its length 60 cm. Adding another 100-N weight will make the spring’s length

A) 60 cm.
B) 70 cm.
C) 80 cm.
D) 100 cm.
E) 120 cm.

B) 70 cm.

Practice test 11-14

A kilogram of peaches have more skin area than a kilogram of
A) blueberries.
B) grapefruits.
C) grapes.
D) Each has the same skin area.
B) grapefruits.

Practice test 11-14

A solid glass ball weighs 1 newton. One with twice the diameter weighs
A) 1 N.
B) 2 N.
C) 3 N.
D) 4 N.
E) more than 4 N.
E) more than 4 N.

Practice test 11-14

Eight little spheres of mercury coalesce to form a single sphere. Compared to the combined surface areas of the eight little spheres, the surface area of the big sphere is
A) one eighth.
B) one quarter.
C) one half.
D) the same.
E) double.
D) the same.

Practice test 11-14

If each dimension of a steel bridge is scaled up ten times, its strength will be multiplied by about
A) ten and its weight by ten also.
B) one hundred, but its weight by one thousand.
C) one thousand, and its weight by one hundred.
D) none of these.
B) one hundred, but its weight by one thousand.

Practice test 11-14

The pressure at the bottom of a jug filled with water does NOT depend on

A) the acceleration due to gravity.
B) water density.
C) the height of the liquid.
D) surface area of the water.
E) none of these

D) surface area of the water.

Practice test 11-14

What is the weight of water displaced by a 100-ton floating ship?

A) less than 100 tons
B) 100 tons
C) more than 100 tons
D) 100 cubic meters
E) depends on the ship’s shape

B) 100 tons
Practice test 11-14
Compared to the density of water, the density of a fish is

A) more.
B) less.
C) the same.

C) the same.

Practice test 11-14

A rock suspended by a string weighs 5 N out of water and 3 N when submerged. What is the buoyant force on the rock?

A) 8 N
B) 5 N
C) 3 N
D) 2 N
E) none of these

D) 2 N

Practice test 11-14

Surface tension of liquids

A) increases when wetting agents are added.
B) decreases as the liquid temperature increases.
C) is about the same for all liquids.
D) results from a thin molecular membrane beneath the liquid surface.
E) is the reason a steel ship will float.

B) decreases as the liquid temperature increases.

Practice test 11-14

Atmospheric molecules do not fly off into outer space because of

A) their relatively high speeds.
B) their relatively low densities.
C) Earth gravitation.
D) cohesive forces.

C) Earth gravitation.

Practice test 11-14
Test 11-14

Atmospheric pressure is caused by the

A) density of the atmosphere.
B) weight of the atmosphere.
C) temperature of the atmosphere.
D) effect of the sun’s energy on the atmosphere.

B) weight of the atmosphere.

Practice test 11-14

A common 5-liter metal can will float in air if it is

A) evacuated of air.
B) filled with a very large amount of helium.
C) thrown high enough.
D) A can will not float in air unless the displaced air weighs more than the can and its contents.

D) A can will not float in air unless the displaced air weighs more than the can and its contents.

Practice test 11-14

Gas pressure inside an inflated stretched balloon is actually

A) less than air pressure outside the balloon.
B) equal to air pressure outside the balloon.
C) greater than air pressure outside the balloon.
D) impossible to determine without knowing the type of gas.

C) greater than air pressure outside the balloon.

Practice test 11-14

As a woman holding her breath swims deeper and deeper beneath the water’s surface, her density

A) increases.
B) decreases.
C) remains the same.

A) increases.

Practice test 11-14
Test 11-14

A swimmer cannot use a long hose to snorkel more than a meter deep because air

A) in the lungs cannot easily be expelled.
B) tends to liquify in the snorkel tube.
C) is buoyed up leaving the swimmer breathless.
D) at the surface will not freely enter the higher-pressure region in the compressed lungs.
E) all of these

D) at the surface will not freely enter the higher-pressure region in the compressed lungs.

Practice test 11-14

The main difference between gases and plasmas has to do with

A) the kinds of elements involved.
B) interatomic spacing.
C) electrical conduction.
D) fluid pressure.
E) the proportion of matter to antimatter in the universe.

C) electrical conduction.

Practice test 11-14

Solid matter is mostly empty space. The reason solids don’t fall through one another is because

A) atoms are constantly vibrating, even at absolute zero.
B) of nuclear forces.
C) of gravitational forces.
D) of electrical forces.
E) none of these

D) of electrical forces.

test 11-14

Compared to the atoms that make up the body of an elderly person, the atoms that make up the body of a newborn baby are

B) actually older.
C) the same age.

C) the same age.

test 11-14

If a gram of antimatter meets a kilogram of matter, the amount of mass to survive is

A) 1 gram.
B) 999 grams.
C) 1 kilogram.
D) 1.1 kilogram.

B) 999 grams.

test 11-14

If a pair of helium nuclei are fused together, the result is

A) helium isotope.
B) lithium.
C) beryllium.
D) boron.
E) carbon.

C) beryllium.

test 11-14

Compared to a bar of pure gold, the density of a pure gold ring is

A) less
B) slightly more
C) the same
D) much more

C) the same

Practice test 11-14

What makes an isotope distinct?

A) the number of protons
B) the number of neutrons
C) the number of electrons
D) the total mass of all the particles
E) none of these

B) the number of neutrons

test 11-14

A loaf of bread is compressed, its

A) molecules become harder
B) density increases
C) density decreases
D) surface tension becomes less
E) none of these

B) density increases

Test 11-14

If the volume of an object were to double while its volume remains the same, its density would

A) halve.
B) double.
C) stay the same.
D) become four times as great.

A) halve

Test 11-14

When a load is placed on the middle of a horizontal beam supported at each end, the bottom part of the beam undergoes

A) tension.
B) compression.

A) tension.

Test 11-14

Compared to the volume of a kilogram of feathers, the volume of a kilogram of lead is

A) less.
B) more.
C) the same.

A) less.

Test 11-14

A strong spring is stretched 10 cm by a suspended weight. If the weight is doubled, the spring will stretch

A) no more.
B) another 5 cm, making the total stretch 15 cm.
C) another 10 cm, making the total stretch 20 cm.
D) another 30 cm, making the total stretch 40 cm.
E) more than another 30 cm.

C) another 10 cm, making the total stretch 20 cm.

Test 11-14

A metal block has a density of 5000 kg per cubic meter and a volume of 2 cubic meters. What is the block’s mass?

A) 1000 kg
B) 2500 kg
C) 5000 kg
D) 10,000 kg
E) none of these

D) 10,000 kg

Practice test 11-14

Doubling the linear size of an object multiplies its area by

A) 2 and its volume by 4.
B) 4 and its volume by 8.
C) 8 and its volume by 16.
D) none of these

B) 4 and its volume by 8.

Test 11-14

Which cooks faster in boiling oil?

A) a whole potato.
B) a sliced potato.
C) Both cook the same.

B) a sliced potato.

Test 11-14

If a pencil’s length and diameter are both multiplied by 10, then its volume is multiplied by

A) 10.
B) 100.
C) 1000.
D) 10,000.
E) none of these

C) 1000.

Test 11-14

In cold weather, your hands will be warmer if you wear

A) gloves.
B) mittens.
C) Both will be the same.

B) mittens

Test 11-14

The pressure in a liquid depends on liquid

A) density.
B) depth.
C) both of these
D) neither of these

C) both of these

Test 11-14

The reason that buoyant force acts upward on a submerged object is that

A) it acts in a direction to oppose gravity.
B) if it acted downward, nothing would float.
C) the weight of fluid displaced reacts with an upward force.
D) upward pressure against the bottom is greater than downward pressure against the top of the submerged object.

D) upward pressure against the bottom is greater than downward pressure against the top of the submerged object.

Test 11-14

A fish normally displaces its own

A) volume of water.
B) weight of water.
C) both of these
D) neither of these

C) both of these

Test 11-14

When an object is partly or wholly immersed in a liquid, it is buoyed up

A) by a force equal to its own weight.
B) by a force equal to the weight of liquid displaced.
C) and floats because of Archimedes principle.
D) but nevertheless sinks.
E) none of these

B) by a force equal to the weight of liquid displaced.

Test 11-14

The reason a life jacket helps you float is

A) the jacket makes you weigh less.
B) the jacket has the same density as an average human.
C) the jacket repels water.
D) if you sink, the jacket sinks.
E) the density of both you and the jacket together is less than your density alone.

E) the density of both you and the jacket together is less than your density alone.

Test 11-14

When holes are drilled through the wall of a water tower , water will spurt out the greatest horizontal distance from the hole closest to

A) the bottom of the tower.
B) the middle of the tower.
C) the top of the tower.
D) The horizontal distance will be the same for all holes.

A) the bottom of the tower.

Test 11-14

Lobsters live on the bottom of the ocean. The density of a lobster is

A) greater than the density of sea water.
B) equal to the density of sea water.
C) less than the density of sea water.

A) greater than the density of sea water.

Test 11-14

Ice cubes submerged at the bottom of a liquid indicate that the liquid

A) produces no buoyant force on the ice.
B) has dissolved air.
C) is warmer than the ice.
D) is not displaced by the submerged ice.
E) is less dense than ice.

E) is less dense than ice.

Test 11-14

A block of wood weighing 5 N in air, is difficult to fully submerge in a pool of mercury because the buoyant force when fully submerged is

A) less than 5 N.
B) 5 N.
C) much more than 5 N.

C) much more than 5 N.

Test 11-14

Buoyant force is greatest on a submerged

A) 1-cubic centimeter block of lead.
B) 1-cubic centimeter block of aluminum.
C) is the same on each

C) is the same on each

Test 11-14

The ratio of output force to input force of a hydraulic press will be equal to the ratio of the output and input piston

A) diameters.
B) areas.
D) all of these
E) none of these

B) areas.

Test 11-14

Surface tension is a direct result of

A) viscosity.
B) Archimedes’ principle.
C) adhesive forces between molecules in a liquid or solid.
D) cohesive forces between molecules in a liquid.

D) cohesive forces between molecules in a liquid.

Test 11-14

A balloon is buoyed up with a force equal to the

A) weight of air it displaces.
B) density of surrounding air.
C) atmospheric pressure.
D) weight of the balloon and contents.
E) all of these

A) weight of air it displaces.
Test 11-14
The air in this room has

A) mass.
B) weight.
C) energy.
D) all of these
E) none of these

D) all of these

Test 11-14

On a windy day, atmospheric pressure

A) remains unchanged
B) increases
C) decreases

C) decreases

Test 11-14

Consider two mercury barometers, one with twice the cross-sectional area of the other. Neglecting capillarity, mercury in the smaller tube will rise

A) the same height as in the larger tube.
B) twice as high as mercury in the larger tube.
C) four times as high as mercury in the larger tube.
D) more than four times as high as in the larger tube.
E) none of these

A) the same height as in the larger tube.

Test 11-14

As a high-altitude balloon sinks lower and lower into the atmosphere, it undergoes a decrease in

A) volume.
B) density.
C) weight.
D) mass.
E) none of these

A) volume.

Test 11-14

Suppose you are standing on a weighing scale and all of a sudden the atmosphere vanished. The reading on the scale would

A) increase.
B) decrease.
C) remain the same.
D) quickly reduce to zero.

A) increase.

Test 11-14

Which of the following bodies is comprised mostly of plasma?
A) Earth
B) Moon
C) Sun
D) all of these
E) none of these
C) Sun

Test 11-14

When you touch a cold piece of ice with your finger, energy flows

A) from your finger to the ice.
B) from the ice to your finger.
C) actually, both ways.

A) from your finger to the ice.

Homework 15
Test 15-18

Heat energy travels from an object with a high

A) internal energy to an object with a lower internal energy.
B) temperature to an object with a lower temperature.
C) Both of these, for they say essentially say the same thing.
D) None of the above choices are true.

B) temperature to an object with a lower temperature.

Homework 15
Practice Test 15-18

A substance that heats up relatively quickly has a
A) high specific heat.
B) low specific heat.
C) high conductivity.
D) low conductivity.
B) low specific heat.

Homework 15
Test 15-18

Heat energy is measured in units of

A) joules.
B) calories.
C) Both of these

B) calories.

Homework 15
Test 15-18

The moderate temperatures of islands throughout the world has much to do with water’s

A) poor conductivity.
B) vast supply of internal energy.
C) high specific heat.
D) high evaporation rate.
E) absorption of solar energy.

C) high specific heat.

Homework 15

Ice has a lower density than water because ice

A) sinks.
B) molecules are more compact in the solid state.
C) molecules vibrate at lower rates than water molecules.
D) is made of open-structured, hexagonal crystals.
E) density decreases with decreasing temperature.

D) is made of open-structured, hexagonal crystals.

Homework 15
Test 15-18

As a piece of metal with a hole in it cools, the diameter of the hole

A) increases.
B) decreases.
C) remains the same.

B) decreases.

Homework 15
Test 15-18

When a bimetallic bar made of copper and iron strips is heated, the bar bends toward the iron strip. The reason for this is

A) iron gets hotter before copper.
B) copper gets hotter before iron.
C) copper expands more than iron.
D) iron expands more than copper.
E) none of these

C) copper expands more than iron.

Homework 15
Test 15-18

During a very cold winter, water pipes sometimes burst. The reason for this is

A) the ground contracts when colder, pulling pipes apart.
B) water expands when freezing.
C) water contracts when freezing.
D) the thawing process releases pressure on the pipes.
E) none of these

B) water expands when freezing.

Homework 15
Test 15-18

The white-hot sparks that strike your skin from a 4th-of-July-type sparkler don’t harm you because

A) they have a low temperature.
B) the energy per molecule is very low.
C) the energy per molecule is high, but little energy is transferred because of the few molecules in the spark.

C) the energy per molecule is high, but little energy is transferred because of the few molecules in the spark.

Homework 16
Practice Test 15-18

Metals are both good heat conductors and good electrical conductors because of the

A) similarity between thermal and electrical conductive properties.
B) looseness of outer electrons in metal atoms.
C) relatively high densities of metals.
D) high elasticity of metals.
E) ability of metals to transfer energy easily.

B) looseness of outer electrons in metal atoms.

Homework 16
Practice Test 15-16

Your feet feel warmer on a rug than on a tile floor because a rug

A) is usually warmer than tile.
B) is a better insulator than tile.
C) for the same mass has more internal energy than tile.
D) all of these
E) none of these

B) is a better insulator than tile.

Homework 16
Practice Test 15-18

It is commonly thought that a can of beverage will cool faster in the coldest part of a refrigerator. Knowledge of Newton’s law of cooling

A) supports this common knowledge.
B) shows this common knowledge is false.

A) supports this common knowledge.

Homework 16
Test 15-18

One of the main reasons one can walk barefoot on red-hot coals of wood without burning the feet has to do with

A) low temperature of the coals.
B) low thermal conductivity of the coals.
C) mind over matter techniques.

B) low thermal conductivity of the coals.

Homework 16
Test 15-18

In a mixture of hydrogen gas, oxygen gas, and nitrogen gas, the molecules with the greatest average speed are those of

A) hydrogen.
B) oxygen.
C) nitrogen.
D) All will have the same average speed at the same temperature.

A) hydrogen.

Homework 16

The reason the sun’s radiant energy is of shorter wavelengths than the Earth’s is because the sun

A) has much more internal energy.
B) has a higher temperature than the Earth.
C) is an energy source while the Earth is primarily an energy receiver.

B) has a higher temperature than the Earth.

Homework 16

If you were caught in freezing weather with only a candle for heat, you would be warmer in

A) an igloo.
B) a tent.
C) a wooden house.
D) a car.

A) an igloo.

Homework 16

A good reflector of radiation is a

Homework 16

When a volume of air is compressed, its temperature

A) increases.
B) decreases.
C) neither increases nor decreases.

A) increases.

Homework 16
Test 15-18

Both black and white road surfaces radiate energy. If both roads start the night at the same temperature, at the end of a starry night the cooler road surface will be

A) the black surface.
B) the white surface.
C) Neither – there is no difference.

A) the black surface.

Homework 16

Evaporation is a cooling process and condensation is

A) a warming process.
B) a cooling process also.
C) neither a warming nor cooling process.

A) a warming process.

Homework 17
Test 15-18

To say that evaporation is a cooling process is to say that the

A) more energetic particles escape.
B) more energetic particles remain in the water.
C) the less energetic particles escape.

A) more energetic particles escape.

Homework 17

When a gas is changed to a liquid state, the gas

A) releases energy.
B) absorbs energy.
C) neither releases nor absorbs energy.
D) both releases and absorbs energy.

A) releases energy.

Homework 17
Test 15-18

Boiling water does not increase in temperature when additional heat is applied because

A) added input energy doesn’t increase the water’s internal energy.
B) the increased heating produces increased boiling, and therefore increased cooling.

B) the increased heating produces increased boiling, and therefore increased cooling.

Homework 17
Test 15-18

To increase the temperature of 50 grams of water by 2 Celsius degrees requires

A) 0.04 calorie.
B) 2 calories.
C) 4.18 calories.
D) 25 calories.
E) 100 calories.

E) 100 calories.

Homework 17
Test 15-18

Food cooked in boiling water at a mountain top cooks slower than when cooked at sea level. If the temperature under the pot of boiling water is increased, the food will cook
A) faster at the mountain top.
B) faster at sea level.
C) faster at both places.
D) no differently than it did before the increase.
D) no differently than it did before the increase.

Homework 17
Practice Test 15-18

A refrigerator

A) produces cold.
B) causes internal energy to disappear.
C) removes internal energy from inside the refrigerator.
D) changes heat into cold.
E) none of these

C) moves internal energy from inside to outside the refrigerator.

Homework 17
Practice Test 15-18

On a humid day, water condenses on the outside of a glass of ice water. This phenomenon occurs mainly because of
A) the porosity of glass.
B) capillary action.
C) adhesion of water molecules to glass.
D) the saturation of cooled air.
E) evaporation.
D) the saturation of cooled air.

Homework 17

Consider a steaming aluminum soda-pop can that contains a small amount of boiling water. When it is quickly inverted into a bath of cooler water the can is dramatically crushed by atmospheric pressure. This occurs because the pressure inside the can is rapidly reduced by

A) contact with the relatively cool water.
B) sudden slowing of the air and steam molecules inside.
C) condensation of steam inside.
D) reduced internal energy.
E) rapid conduction of heat to the relatively cool water.

C) condensation of steam inside.

Homework 17

Stored potatoes, beets, and rutabagas freeze at temperatures below zero degrees Celsius (rather than at exactly zero) because

A) they are good radiators of energy.
B) they are good absorbers of radiant energy.
C) the water in them contains dissolved salts and sugars.
D) they are very dense.

C) the water in them contains dissolved salts and sugars.

Homework 17
Practice Test 15-18

If you run a refrigerator in a closed room with the refrigerator door open, the room temperature will

A) increase.
B) decrease.
C) remain unchanged.

A) increase.

Homework 18
Practice Test 15-18
Test 15-18

During an adiabatic compression of an ideal gas

A) the internal energy of the gas remains constant.
B) the temperature of the gas does not change.
C) no heat is supplied to or removed from the gas.
D) no work is done on the gas.

C) no heat is supplied to or removed from the gas.

Homework 18
Test 15-18

A quantity of water has more entropy when it is

A) frozen ice.
B) boiling.
C) at room temperature.

B) boiling.

Homework 18
Test 15-18

Suppose you rapidly stir some raw eggs with an eggbeater. The temperature of the eggs will

A) increase.
B) decrease.
C) remain unchanged.

A) increase.

Homework 18
Practice Test 15-18

If a blob of air is swept upward, with no heat input or output, its temperature

A) increases.
B) decreases.
C) remains the same.

B) decreases.

Homework 18
Test 15-18

The amount of energy ultimately converted to heat by a light bulb is about

A) 15%.
B) 30%.
C) 45%.
D) 60%.
E) 100%.

E) 100%.

Homework 18

As a system becomes more disordered, entropy
A) increases.
B) decreases.
C) remains the same.
A) increases.

Homework 18

Sue’s refrigerator is built into the wall of her kitchen, so that it exhausts heat to the outdoors rather than into the room. If Sue tries to cool her kitchen by leaving the refrigerator door open, the room temperature will
A) increase at least slightly.
B) decrease at least slightly.
C) remain unchanged.
B) decrease at least slightly.

Homework 18

Consider a piece of metal that is at 10 degrees C. If it is heated until it has twice the internal energy, its temperature will be

A) 20 degrees C.
B) 273 degrees C.
C) 293 degrees C.
D) 566 degrees C.

C) 293 degrees C.

Homework 18

The ideal efficiency for a heat engine operating between the temperatures of 227 degrees C and 27 degrees C is

A) 20%.
B) 25%.
C) 40%.
D) 88%.

C) 40%.

Homework 18
Test 15-18

The fact that a thermometer “takes its own temperature” illustrates

A) thermal equilibrium.
B) energy conservation.
C) the difference between heat and internal energy.
D) the fact that molecules are constantly moving.

A) thermal equilibrium.

Practice Test 15-18

The moderate temperatures of islands throughout the world has much to do with water’s

A) poor conductivity.
B) vast supply of internal energy.
C) high specific heat.
D) high evaporation rate.
E) absorption of solar energy.

C) high specific heat.

Practice Test 15-18

Compared to a giant iceberg, a hot cup of coffee has

A) more internal energy and higher temperature.
B) higher temperature, but less internal energy.
C) a greater specific heat and more internal energy.
D) none of these

B) higher temperature, but less internal energy.

Practice Test 15-18

Microscopic slush in water tends to make the water density

A) greater.
B) less.
C) no change

B) less.

Practice Test 15-18

Ice tends to form first at the

A) surface of bodies of water.
B) bottom of bodies of water.
C) surface or bottom depending on the water depth.

A) surface of bodies of water.

Practice Test 15-18

When an iron ring is heated, the hole becomes

A) smaller.
B) larger.
C) neither smaller nor larger.
D) either smaller or larger, depending on the ring thickness.

B) larger.

Practice Test 15-18

If glass expanded more than mercury, then the column of mercury in a mercury thermometer would rise when the temperature

A) increases.
B) decreases.
C) neither of these

B) decreases.

Practice Test 15-18

Consider a closed, sealed can of air placed on a hot stove. The contained air undergoes an increase in

A) mass.
B) pressure.
C) temperature.
D) two of these

D) two of these

Practice Test 15-18

When water at 4 degrees C is heated it expands. When water at 4 degrees C is cooled, it

A) contracts.
B) expands.
C) neither contracts nor expands.

B) expands.

Practice Test 15-18

The temperature at the bottom of Lake Tahoe, high in the Sierra Nevada Mountains in California, at this moment is

A) below 4 degrees C.
B) 4 degrees C.
C) above 4 degrees C.
D) uncertain.

B) 4 degrees C.

Practice Test 15-18

If you measure a plot of land with a brass tape on a cold day, the actual amount of land you have will be

A) smaller than measured.
B) larger than measured.
C) the same.

Practice Test 15-18

At the same temperature, which move with the greater speed in the air?

A) very light molecules
B) heavier molecules
C) All will have equal average speeds.

A) very light molecules

Practice Test 15-18

An object will normally be a net radiator of energy when its temperature is

A) higher than its surroundings.
B) lower than its surroundings.
C) neither of these

A) higher than its surroundings.

Practice Test 15-18

The planet Earth loses heat mainly by

A) conduction.
B) convection.
D) all of these

Practice Test 15-18

If you double the pressure of an ideal gas while keeping the temperature constant the average kinetic energy of the molecules

A) increases by more than twice
B) increases by less than twice
C) remains unchanged
D) is doubled

C) remains unchanged

Practice Test 15-18
Test 15-18

Newton’s law of cooling applies to objects that are

A) cooling.
B) heating.
C) both of these
D) none of these

C) both of these

Practice Test 15-18

Both black and white road surfaces absorb sunlight. At the end of a sunny day the warmer road surface will be

A) the black surface.
B) the white surface.
C) Neither – there is no difference.

A) the black surface.

Practice Test 15-18

If a volume of air is warmed, it expands. If a volume of air expands, it

A) warms.
B) cools.
C) neither warms nor cools.

B) cools.

Practice Test 15-18

Double the absolute temperature of helium gas and the average speed of its molecules

A) less than doubles.
B) doubles.
C) more than doubles.

A) less than doubles.

Practice Test 15-18

A good absorber of radiation is a

C) good reflector
D) none of these

Practice Test 15-18

The molecules in a room-temperature glass of water jostle around at

A) a great variety of speeds.
B) much the same rates of speed.
C) a very small range of speeds.

A) a great variety of speeds.

Practice Test 15-18

Evaporation is a cooling process because

A) heat is radiated during the process.
B) of conduction and convection.
C) the more energetic molecules are able to escape the liquid.
D) the temperature of the remaining liquid decreases.
E) none of these

C) the more energetic molecules are able to escape the liquid.

Practice Test 15-18

A hot dog pants

A) to help evaporation occur in its mouth and bronchial tract.
B) to bring more oxygen into its lungs.
C) for no particular reason – some things just happen.
D) to impress dogs of the opposite sex.

A) to help evaporation occur in its mouth and bronchial tract.

Practice Test 15-18

When heat is added to boiling water, its temperature

A) increases.
B) decreases.
C) does not change.

C) does not change

Practice Test 15-18

For increased atmospheric pressure, the boiling temperature of a liquid

A) goes down.
B) goes up.
C) remains at 100 degrees C.

B) goes up.

Practice Test 15-18

Water will evaporate quicker if it

A) choices C,D,E are all correct
B) One or two of the choices below are not correct
C) is spread out in a thin sheet
D) is preheated to 100 degrees C
E) is surrounded by hot air

A) choices C,D,E are all correct

Practice Test 15-18

When snow forms in clouds, the surrounding air

A) warms.
B) cools.
C) neither warms nor cools.

A) warms.

Practice Test 15-18

When a block of ice at zero degrees Celsius melts, the ice

A) absorbs energy from its environment.
B) releases energy to its environment.
C) absorbs energy and gets warmer.
D) releases energy and gets warmer.
E) absorbs energy but does not change its temperature.

A) absorbs energy from its environment.*

Practice Test 15-18

The lowest temperature possible in nature is

A) 0 degrees C.
B) -273 degrees C.
C) 4 K.

B) -273 degrees C.

Practice Test 15-18
Test 15-18

A volume of air has a temperature of 0 degrees Celsius. An equal volume of air that is twice as hot has a temperature of

A) 0 degrees C.
B) 64 degrees C.
C) 100 degrees C.
D) 273 degrees C.

D) 273 degrees C.

Practice Test 15-18
Test 15-18

To wholly convert a given amount of heat energy into mechanical energy is

A) possible using a steam engine.
B) possible using an atomic reactor.
C) possible using a simple machine.
D) impossible regardless of the technique used.

D) impossible regardless of the technique used.

Practice Test 15-18

A temperature inversion occurs when the upper layers of air are

A) warmer than the lower regions of air.
B) cooler than the lower regions of air.
C) at the same temperature as lower regions of air.

A) warmer than the lower regions of air.

Practice Test 15-18
Test 15-18

To totally convert a given amount of mechanical energy into heat is

A) possible.
B) impossible.

A) possible.

Practice Test 15-18
Test 15-18

A) warmer still.
B) cooler.
C) neither warmer nor cooler.

B) cooler.

Practice Test 15-18

The Earth’s atmosphere gets most of its heat

A) near the surface of the Earth.
B) at high altitudes closer to the sun.
C) from the Earth’s core.

A) near the surface of the Earth.

Practice Test 15-18

A) only in the atmosphere.
B) only in the oceans
C) only in the Earth’s mantle.
D) in both the atmosphere and the oceans
E) in the atmosphere, oceans and the Earth’s mantle.

E) in the atmosphere, oceans and the Earth’s mantle

Practice Test 15-18

One hundred joules of heat is added to a system that performs 60 joules of work. The internal energy change of the system is

A) 0 J.
B) 40 J.
C) 60 J.
D) 100 J.

B) 40 J.

Practice Test 15-18

As a blob of air at a high elevation sinks to a lower elevation with no heat input or output, its temperature

A) increases.
B) decreases.
C) remains the same.

A) increases.

Practice Test 15-18

On a chilly 10-degree-C day, your friend who likes cold weather, wishes it were twice as cold (half as hot). Taken literally, this temperature would be

A) -131.5 degrees C
B) -141.5 degrees C
C) 10 degrees C
D) 0 degrees C
E) 5 degrees C

A) -131.5 degrees C

Practice Test 15-18

The ideal efficiency for a heat engine operating between temperatures of 2700 K and 300 K is
A) 10%.
B) 24%.
C) 80%.
D) 89%.
D) 89%.

Test 15-18

Before ice can form on a lake, all the water in the lake must be cooled to

A) zero degrees C.
B) 4 degrees C.
C) minus 32 degrees C.
D) None of the above. Ice can form at the surface regardless of the water temperature below.

B) 4 degrees C.

Test 15-18

Consider a sample of water at 0 degrees C. If the temperature is slightly increased, the volume of the water
A) increases.
B) decreases.
C) remains the same.
B) decreases.

Test 15-18

Aluminum has a specific heat capacity more than twice that of copper. Place equal masses of aluminum and copper wire in a flame and the one to undergo the fastest increase in temperature will be
A) copper.
B) aluminum.
C) both the same
A) copper.

Test 15-18

Room temperature on the Kelvin scale is about
A) 100 K.
B) 200 K.
C) 300 K.
D) 400 K.
E) more than 400 K.
C) 300 K.

Test 15-18

The fact that desert sand is very hot in the day and very cold at night is evidence that sand has
A) a low specific heat.
B) a high specific heat.
C) no specific heat.
A) a low specific heat.

Test 15-18

Pour a liter of water at 40 degrees C into a liter of water at 20 degrees C and the final temperature of the two becomes
A) less than 30 degrees C.
B) at or about 30 degrees C.
C) more than 30 degrees C.
B) at or about 30 degrees C.

Test 15-18

Substances absorb heat energy by the process of
A) conduction.
B) convection.
D) all of these
D) all of these

Test 15-18

A good heat conductor is
A) a poor insulator.
B) a good insulator.
C) neither a poor nor a good insulator.
A) a poor insulator.

Test 15-18

Energy transfer by convection is primarily restricted to
A) solids.
B) liquids.
C) gases.
D) fluids.
E) none of these
D) fluids.

Test 15-18

If a solid object radiates more energy than it absorbs, its
A) internal energy increases
B) internal energy decreases.
B) internal energy decreases.

Test 15-18

Waves emitted by the sun and terrestrial wave emissions are
A) the same except for their frequencies and wavelengths.
B) entirely different kinds of waves.
C) identical.
A) the same except for their frequencies and wavelengths.

Test 15-18

A liter of hot water will cool to room temperature faster in a
A) black pot.
B) silver pot.
A) black pot.

Test 15-18

Hydrogen and oxygen molecules in a gas sample have the same temperature. This means the hydrogen molecules, on the average, have the same
A) speed and the same kinetic energy.
B) speed, but more kinetic energy.
C) speed, but less kinetic energy.
D) kinetic energy, but more speed.
E) kinetic energy, but less speed.
D) kinetic energy, but more speed.

Test 15-18

We are warmed by condensation because water molecules in the air that strike our bodies
A) transfer some of their kinetic energy to us.
B) gain kinetic energy as they change state.
C) form an insulating layer on our bodies.
A) transfer some of their kinetic energy to us.

Test 15-18

Increased air pressure on the surface of hot water tends to
A) prevent boiling.
B) promote boiling.
C) Neither choice A nor choice B is true.
D) Choice A and choice B are both true.
A) prevent boiling.

Test 15-18

Near the top of a mountain, water in an open pot boils at
A) a higher temperature than at sea level.
B) a lower temperature than at sea level.
C) the same temperature as at sea level.
D) None of the above choices are true.
B) a lower temperature than at sea level.

Test 15-18

Hot water has a relatively high rate of
A) evaporation.
B) condensation.
C) conductivity.
D) convection.
A) evaporation.

Test 15-18

To turn ice at zero degrees Celsius to water at zero degrees Celsius, we must add
A) temperature.
B) energy.
C) force.
D) time.
E) It can’t be done – water is always warmer than that.
B) energy.

Test 15-18

Melting snow
A) warms the surrounding air.
B) cools the surrounding air.
C) neither warms nor cools the surrounding air.
B) cools the surrounding air.

Test 15-18

If you want to cook eggs by boiling them while in the mountains, then compared to sea-level cooking, you should
A) use a hotter flame.
B) boil the eggs for a shorter time.
C) boil the eggs for a longer time.
D) None of the above choices are true.
C) boil the eggs for a longer time.

Test 15-18

Morning dew on the grass is a result of
A) evaporation .
B) the open-structured form of water crystals.
C) air pressure on water vapor.
D) condensation
D) condensation

Test 15-18

Ice is put in a cooler to cool the contents. To speed up the cooling process, the ice can be
A) wrapped in newspaper.
B) drained of ice water periodically.
C) kept out of contact with the food.
D) kept in one solid chunk.
E) covered with salt.
E) covered with salt

Test 15-18

The greater the difference in temperature between the input reservoir and the output reservoir for a heat engine, the
A) greater the efficiency.
B) less the efficiency.
C) Neither – efficiency of a heat engine doesn’t depend on temperature difference.
A) greater the efficiency.

Test 15-18

Entropy can be

A) sometimes destroyed but never created
B) created but not destroyed
C) neither created nor destroyed

B) created but not destroyed

Test 15-18

When a system does work and no heat is added to the system, its temperature
A) increases.
B) decreases.
C) remains unchanged.
B) decreases.

Test 15-18

When a volume of air expands against the environment and no heat enters or leaves, the air temperature will
A) increase.
B) decrease.
C) remain unchanged.
B) decrease.

Test 15-18