Physics: 1-11

Physics is the most basic Science because
All of the above
Which one of the following problems would not be part of Physics?
Identifying all the bones in the human body
Which of the following steps is not a part of the scientific method?
Repeat the Experiments until the answers math the predictions
A hypothesis is
an educated guess that has yet to be proven by experiment
A scientific fact is
close agreement by competent observers of observations of the same phenomena.
A theory is
a synthesis of a large collection of information including well tested guesses.
The difference between a hypothesis and a theory is that a hypothesis is
an educated guess where as a theory has been tested successfully many times in many ways.
One difference between a hypothesis and a theory is that a hypothesis
is a guess that has not been well tested whereas a theory is a synthesis of well tested guesses
Which of these is a scientific hypothesis
Atoms are the smallest particles of matter that exist
A scientific hypothesis may turn out to be right or it may turn out to be wrong. If it is a valid hypothesis there must be a test for proving that it is
wrong
To test a scientific hypothesis you would
set up many experiments and look at the results
Which of the following statements is not true?
A good scientist is influenced by his or her likes and dislikes
Science, art and religion do not contradict one another because
all three have different domains
Which of the following is a reason to express scientific findings mathematically?
the findings become easier to verify by experiment
Which of the following is a problem that some people blame on technology?
widespread pollution
A science teacher, an art instructor and a religious studies teacher are arguing about their respective disciplines. Which of the following could be a claim that each teacher makes?
The goal of my discipline is to search for order and meaning in the world.
A 15-N force and a 45-N force act on an object in opposite directions. What is the net force on the object
3oN
What is the maximum resultant possible when adding a 2-N force to and 8-N force?
10N
A 5-N force and a 30-N force act in the same direction on an object. What is the net force on the object ?
35N
What is the minimum resultant possible when adding a 5-N force to an 8-N force?
5N
Equilibrium occurs when
all of the above
A girl whose weight is 500 N hands from the middle of a bar supported by two vertical strands of rope. What is the tension in each strand?
250N
The weight of a person can be represented by a vector that acts
straight down, even if the person is standing on a hill
What would be the safest war to put up a clothesline
with some slack in the line
A barge is being pulled along a canal by two ropes that make equal angles with the direction in which the barge points. Assuming the two pulls on the barge are equal, in what direction does the barge move?
Both B and C: B-It moves straight ahead C- it moves in the direction of the resultant force on it
A clothesline os stretched between two trees. A tire hangs in the middle of the line and the two halves of the line make equal angles with the horizontal. The tension in the line is
more than half the tires weight
A 100-N lantern is suspended by a pair of ropes with 120 degrees between them (Each 60 degrees from the vertical). The tension in each rope is
100N
What is needed to describe a vector quantity?
both magnitude and direction
A scalar quantity has
only magnitude
In order to find the components of a vector, you should
all of the above
You are helping your aunt move a piano on wheels from one too to another. When you push the piano horizontally, it moves at a constant speed. What can you say about the piano.
It is in dynamic equilibrium
The basic unit used by scientist to describe length is the:
meter
The value for the speed of light is
186,000 miles/sec
An objects mass on the moon would be the same as its mass on earth.
true
If an object in motion is unchanged, it is said to be:
in dynamic equilibrium
Speed is…….
a measure of how fast something is moving, always measured in terms of a unit of distance divided by a unit of time and the distance covered per unit time
One possible unit of speed is
miles per hour, light years per century and kilometers per hour
When you look at the speedometer in a moving car, you see the car’s
instantaneous speed
A train travels 6 meters in the first second of travel, 6 meters again during the second second of travel and 6 meters again during the third second. Its acceleration is
0 m/s squared
A car starts from rest and after 7 seconds it is moving at 42m/s. What is the car’s average acceleration?
6m/s squared
As an object falls freely in a vacuum, its
velocity increases
In the absence of air resistance, objects fall at constant
acceleration
A ball is thrown upwards and caught when it comes back down. In the absence of air resistance, the speed of the ball when caught would be
more than the speed it had when thrown upwards
Suppose an object is in free fall. Each second the object falls
a larger distance than in the second before
If you drop a feather and a coin at the time in a tube filled with air, which will reach the bottom of the tube first?
the coin
Consider drops of water leaking from a water faucet. As the drops fall they
get farther apart
A ball tossed vertically upward rises, reaches its highest point, and then falls back to its starting point. During this time the acceleration of the ball is always
directly downward
The hang time (time one’s feet are off the ground in a jump) for most athletes is
less than 1 second
When a basketball player jumps to make a shot, once the feet are off the floor, the jumper’s acceleration
is g; no more, no less
Suppose you take a trip that covers 180 km and takes 3 hours to make. Your average speed is
60 km/h
Suppose a car is moving in a straight line and steadily increases its speed. It moves from 35 km/h to 40 km/h the first second and from 40 km/h to 45 km/h the next second. What is the car’s acceleration?
5 km/h x s
A ball is thrown straight up. At the top of its path its instantaneous speed is
0 m/s
A ball is thrown straight up. At the top of its path its acceleration is
about 10 m/s squared
When something falls to the ground, it accelerates. This acceleration is called the acceleration due to gravity and is symbolized by the letter g. What is the value of g on Earth’s surface?
about 10 m/s squared
A car accelerates at 2 m/s. Assuming the car starts from rest, how much time does it need to accelerate to a speed of 20 m/s?
10 seconds
If a freely falling object were somehow equipped with a speedometer, its speed reading would increase each second by
about 10 m/s
A freely falling object starts from rest. After falling for 6 seconds, it will have a speed of about
60 m/s
A freely falling object starts from rest. After falling for 1 second, it will have a speed of about
10 m/s
If a projectile is fired straight up at a speed of 30 m/s, the total time to return to its starting point is about
6 seconds
The vertical height attained by a basketball player who achieves a hang time of a full one second is about
1.2 m
Suppose a jumper claims a hang time of 2 seconds. Then that jumper must be able to jump a vertical distance of
5 m
Acceleration is defined as
the rate at which velocity changes itslef
Galileo found that a ball rolling down one inclined plane would roll how far up another inclined plane?
to nearly its original height
Friction is a force that always acts
opposite to an object’s motion
The law of inertia states that an object
will continue moving at the same velocity unless an outside force acts on it, will continue moving in a straight line unless an outside force acts on it, that is not moving will never move unless a force acts on it and at rest will remain at rest unless acted on by an outside force
The law of inertia applies to
both moving and nonmoving objects
After a cannonball is fired into frictionless space, the amount of force needed to keep it going equals
zero, since no force is necessary to keep it moving
A sheet of paper can be withdrawn from under a container of milk without toppling it if the paper is jerked quickly. The reason this can be done is that
the milk carton has inertia
An object following a straight line path at constant speed
has zero acceleration
Friction
come from microscopic bumps that act as obstructions to the object’s motion, is the name given to the force acting between surfaces sliding past one another, acts in a direction that opposes the motion of an object
One object has twice as much mass as another object. The first object also has twice as much
inertia
Compared to its mass on Earth, the mass of a 10 kg object on the moon is
the same
The mass of a lamb that weighs 110 N is about
11 kg
How much does a 3.0 kg bag of bolts weigh?
29.4 N
A bag of sports equipment has a mass of 10.0 kilograms and a weight of
98 N
An object weighs 30 N on Earth. A second object weighs 30 N on the moon. Which has the greater mass?
the one on the moon
A vector is a quantity that has
C. magnitude and direction
A scalar is a quantity that has
B. magnitude
When representing velocity as a vector
D. all of the above
In order to find the components of a vector, you should
D. all of the above
Which of the following would NOT be considered a projectile?
B. A cannonball rolling down a slope
The horizontal component of a projectile’s velocity is independent of
C. the vertical component of its velocity
In the absence of air friction, the vertical component of a projectile’s velocity doesn’t change as the projectile moves.
A. always false
In the absence of air friction, the horizontal component of a projectile’s velocity doesn’t change as the projectile moves.
B. always true
A the instant a ball is thrown horizontally with a large force, an identical ball is dropped from the same height. Which ball hits the ground first?
A. neither. They both hit the ground at the same time.
A ball is thrown into the air at some angle. At the very top of the ball’s path, its velocity is
D. entirely horizontal
In the absence of air resistance, the angle at which a thrown ball will go the farthest is
C. 45 degrees
A ball thrown in the air will never go as far as physics ideally would predict because
C. air friction slows the ball
At what part of a path foes a projectile have minimum speed?
C. At the top of its path
A cannonball is launched from the ground at an angle of 30 degrees above the horizontal and a speed of 30 m/s. Ideally (no air resistance) the ball will land on the ground with a speed of
C. 30 m/s
A projectile launched horizontally hits the ground in 0.8 seconds. If it had been launched with a much higher speed in the same direction, it would have hit the ground (neglecting Earth’s curvature and air resistance) in
B. 0.8 s
A projectile is fired horizontally in a vacuum. The projectile maintains its horizontal component of speed because it
D. is not acted on by any horizontal forces
An object is dropped and falls freely to the ground with an acceleration of g. It it is thrown upward at an angle instead, its acceleration would be
D. g downward
A baseball is hurled into the air at an angle of 30 degrees above the horizontal and lands on a target if it is thrown at an angle of
D. 60 degrees
A cannonball is launched horizontally from a tower. If the cannon has a barrel velocity of 60 m/s, where will the cannonball be 1 second later? (Neglect air resistance)
C. 60m downrange
After a rock that is thrown straight up reaches the top of its path and is starting to fall back down, its acceleration is (neglecting air resistance)
C. the same as when it was at the top of its path
An airplane flying into a head wind loses ground speed, and an airplane flying with the wind gains ground speed. If an airplane flies at right angles to the wind, then ground speed it
A. more
Jose can jump vertically 1 meter from his skateboard when it is at rest. When the skateboard is moving horizontally, Jose can jump
A. no higher
What is the resultant of a 3-unit vector and 4-unit vector at right angles to each other?
B. 5 units
In Chapter 4, you learned about “hang time,” the time a jumper’s feet are off the ground in a vertical jump. If the jumper runs horizontally and has the same vertical component of takeoff velocity, hang time will be
A. no different
Suppose a small plane can fly at 170 km/h relative to the surrounding air. Suppose also that there is a 60 km/h tailwind. How fast does the plane’s shadow move across the ground?
E. 230 km/h
At the instant a ball is thrown horizontally with a large force, an identical ball is dropped from the same height. Which ball hits the ground first?
A. neither- they both hit the ground at the same time
A cannonball is fired at some angle into the air. In the first second it moves 5 meters horizontally. Assuming it doesn’t hit the ground and air resistance is negligible, how far does it move horizontally in the next second?
C. 5m
In the absence of air resistance, at what other angle will a thrown ball go the same distance as one thrown at an angle of 75 degrees?
A. 15 degrees
A ball is thrown straight upward a 10 m/s. Ideally (no air resistance), the ball will return to the thrower’s hand with a speed of
C. 10 m/s
A cannon with a barrel velocity of 140 m/s launches a cannonball horizontally from a tower. Neglecting air resistance, how far vertically will the cannonball have fallen after 4 seconds?
A. 80m
Accelerations are produced by
forces
How does acceleration of an object change in relation to its mass? it is..
inversely proportional
The acceleration produced by a net force on an object is…
none of the above
When an object reaches terminal velocity its acceleration is..
0 m/s
A 10-kg brick and a 1-kg book are dropped in a vacuum. the force of gravity on the 10kg brick is..
10 times as much as the force on the 1 kg book
When a women stands with two feet on a scale the scale reads 280 N. when she lifts one foot the scale reads…
280 N
Suppose the force of friction on a sliding object is 25 N. the force needed to maintain a constant velocity is..
25N
an apple weights 1-N. the net force on the apple when it is in free fall is..
1 N
A girl pulls on a 10-kg wagon with a constant force of 20 N. what is the wagon’s acceleration?
2 m/s
ab object has a constant mass. A constant force on the object produces constant
acceleration
A force of 3N accelerates a mass of 3 kg at the rate of 1m/s. the acceleration of a mass of 6 kg acted upon by a force of 6 N is
the same
A push on a 1 kilogram brick accelerates the brick. Neglecting friction, to equally accelerate a 10-kilogram brick one would have to push
with 10 times as much force
A rock is thrown vertically into the air. at the very top of its trajectory the net force on it is..
its weight
a box is dragged without acceleration in a straight-line path across a level surface by a force of 13 N. what is the frictional force between the box an the surface
13 N
the unit of pressure is
newtons per square meter
which of the falling would exert the most pressure on the ground?
a women standing in high heel shoes
a tennis ball and solid steel ball with the same diameter are dropped at the same time. which ball has the greater force acting on it?
the steel ball
a tennis ball and solid steel ball with the same diameter are dropped at the same time. in the absence of resistance, which ball has the greater acceleration?
they both have the same acceleration
if you pull horizontally on a desk with a force of 150N and the desk doesn’t move, the friction force must be 150 N. now if you pull with 250 N so the desk slides at a constant velocity, the friction is
250 N
a block is at rest on an incline. the force of friction necessary to prevent the block from sliding increased when the incline angle is
increased
consider a ball rolling down the decreasing slope inside a semicircular bowl(the slope is steep at the top of the rim, get less steep towards the bottom, and is zero (no slope) at the bottom). as the ball rolls from the rim downward toward the bottom, its rate is gaining speed
decreases
a speeding truck locks its brakes and it skids to a stop. if the trucks total mass were doubled, its skidding distance would be
the same
if the force acting on a cart doubles, what happens to the carts acceleration
it doubles
suppose a cart is being moved by a force. if suddenly a load is dumped into the cart so that the cats mass doubles, what happens to the carts acceleration?
it halves
you are on a frozen pond, and the ice starts to crack. if you lie down on the ice and began to crawl……
decreases pressure on ice
a 20 N falling object encounters a 4 N of air resistance. the magnitude of the net force on the object is
16 N
a sports car has a mass of 1500 kg and accelerates at 5 meters per second squared. what is the magnitude the force acting on the sports-car?
7500 N
a tow truck exerts a force of 2000 N on a car, accelerating it at 1m/s. what is the mass of the car?
2000 kg
a jet has a mass of 40,000 kg. the thrust for each of four engines is 20,00 N. what is the jets acceleration when taking off?
2 m/s
you pull horizontally on a 50kg crate with a force of 450N and the friction force on the crate is 250N. the acceleration of the crate is?
4m/s
how much force is needed to accelerate a 4 kg physics book to an acceleration of 2. m/s
8 N
a jumbo jet cruises at a constant velocity when the total thrust of the engines on the jet is 50,000 N. how much air resistance acts on the jet
50,000 N
A 6 N falling object encounters a 6 N of air resistance. the magnitude of the net force on the object is
0 N
if shopping cart A has five times more mass in it than shopping cart B and the two carts are pushed with equal forces, you can expect the acceleration of the shopping cart A to be
1/5 times that of shopping cart B
If a truck has ten times the mass of a car and the two vehicles are pushed with an equal force, you would expect the acceleration of the truck to be
1.10 times that of the car
An unfortunate bug splatters against the windshield of a moving car. Compared to the force of the car on the bug, the force of the bug on the car is
the same.
If your car runs out of gas, why can’t you push on the cars windshield from the inside to move it?
In order for the car to move, a force must be exerted by the car on the ground.
A force is exerted on the tires of a car to accelerate the car along the road. The force is exerted by the
road.
Nelly Newton holds an apple in her hand. If action is Earth pulling on the apple, then reaction is
neither A nor B
A 60-kg person on in-line skates pushes against a wall with a force of 30 N and recoils. What acceleration does that person experience?
0.5 m/s/s
If a horse pulls on a wagon at rest, the wagon pulls back equally on the horse. Can the wagon be set into motion?
Yes, Because there is a net force acting on the wagon.
A helicopter can fly because:
it pushes away with a force greater than the force of Earth’s gravity on the helicopter.
You drive past a farm, and you see a cow pulling a plow to till a field. You have just learned about Newton’s third law, and you wonder how the cow was able to move forward if the plow is exerting equal and opposite force on the cow. Which of the following explains the movement of the cow and plow?
The force exerted by the cow on the plow is smaller than the force that the cow exerts on the ground to move forward.
According to Newton’s third law, if you push gently on something, it will push
gently on you.
In order for newtons third law to occur,
at least two objects and two forces are needed.
As a 600-N woman sits on the floor, the floor exerts a force on her of
600 N.
A pair of blocks, one 2 times as massive as the other, are connected by a compressed spring. When the spring is released, the blocks fly apart. Compared to the heavier block, how many times as fast as the lighter block accelerate?
2 times as fast
Earth pulls on the moon, and similarly the moon pulls on Earth. This is evidence that the
both a and b
A rocket is able to accelerate in the vacuum of space what it fires it’s engines. The force that propels the rocket is the force
of the exhaust gases on the rocket.
Whenever an object exerts a force on another object, the second object exerts a force of the same magnitude, but in the opposite direction to that of the first object.
Always true
If you exert a force of 12,000 N on a 3000 kg car and a 6000 kg truck that are both originally at rest, what will be the resulting acceleration of the objects?
The car will accelerate 4 m/s/s and the truck will accelerate 2/m/s/s.
An archer shoots and arrow. Consider the action force to be the bowstring against the arrow. The reaction to this force is the
arrow’s push against the bowstring.
Forces always occur
in pairs.
Bronco the skydiver falls toward Earth. The attraction of Earth on Bronco pulls him down. The reaction to this force is
Bronco pulling up on Earth.
A player hits a ball with a bat. The action force is the impact of the bat against the ball. What is the reaction to this force?
The force of the ball against the bat
If you push off the ground with a force of 350 N when you jump upward, what force pushes Earth downward?
350 N
A fighter punches a piece of paper in mid air, and brings it from rest up to a speed of 40 m/s in 0.08 seconds. What is the force of impact on the paper if the mass of the paper is 0.01 kg?
5.0 N
Woman weighing 550 N sits on the floor. She exerts a force on the floor of
550 N
A large truck and a small car traveling at the same speed have a head on collision. The vehicle to undergo the greater change in velocity will be
the small car.
Two people have a tug-of-war on low friction ice. One person has two times the mass of the other. Compared to the lighter person, how many times as fast as the heavier person accelerate?
1/2 as much
Two people pull out of rope in a tug-of-war. Each pose with 400 N of force. What is the tension in the rope?
400 N
A player catches a ball. Consider the action force to be the impact of the ball against the players glove. What is the reaction to this force?
The force the glove exerts on the ball
A person is attracted towards the center of earth by a 440 N gravitational force. The force with which Earth is attracted toward the person is
440 N.
As a ball falls, the action force is the pool of earths mass on the ball. What is the reaction to this force?
The pull of the ball’s mass on earth
A high school student hits a nail with a hammer. During the collision, there is a force
on the nail and also on the hammer.
What engine thrust (in Newtons) is required for a rocket of mass 35 kg to leave the launching pad?
350 N
A karate chop delivers a blow of 2300 N to a board that breaks. The force that acts on the hand during this feat
is 2300 N.
Suppose two people, one having three times the mass of the other, pull on opposite sides of a 20-meter rope while on frictionless ice. After a brief time, they meet. The more massive person slides a distance of
5 m.
Suppose you accidentally drive into a tree. Which of the following correctly describes the interaction between your car and the tree?
The car and the tree at mutually exert equal and opposite forces on each other.
An unfortunate bug splatters against the windshield of a moving car. Compared to the deceleration of the car, the deceleration of the bug is
larger.
The momentum of an object is defined as the objects
mass times its velocity
Which has more momentum, a large truck moving at 30 miles per hour or a small truck moving 30 miles per hour
The large truck
Compared to a sports car moving at 30 miles per hour, the same sports car moving at 60 miles has
twice as much momentum
If the momentum of an object changes and its mass remains constant
it is accelerating(or decelerating) there for is a force acting on it, its velocity is changing
The momentum change of an object is equal to the
impulse acting on it
In order to increase the final momentum of a golf ball we could
increase the force acting on it, follow through when hitting the ball, increase the time of contact with the ball, swing as hard as possible
The reason padded dashboards are used in cars is that they
increase the time of impact in a collision
Momentum of a system is conserved only when
there are no forces acting on the system
A collision is considered elastic if
after the collision the objects have the same shape as before the collision
Suppose Katie is standing on a pond where there is no friction between her feet and the ice, in order to get off the ice she can
throw something in the direction opposite to the way she wants to go
which of the following has the largest momentum
a pickup truck traveling down the highway
A freight train rolls along a track with considerable momentum. If it were to roll at the same speed but had twice as much mass its momentum, would be
quadropel
A cannon recoils from launching a cannonball. the speed of the cannons recoil is small because the
cannon has far more than the cannon ball
suppose a cannon is made of a strong but very light material, suppose also that cannonball is more massive than the cannon itself. for such a system
the target would be a safer place that where the cannon operator is located
two objects, A and B have the same size and shape, but A is twice as heavy as B. When they are dropped simultaneously from a tower, they reach the ground at the same time, But A has a higher
momenutm
In order to catch a ball, a baseball player moves his or her hand backward in the direction of the balls motion. Doing this reduces the force of impact on the players hand principally because
the time of impact is increased
A care traveling along the highway needs a certain amount of force exerted on it to stop. More stopping force may be required when the car has
less stoping distance, more momentum, more mass
A cannon fires a cannonball. the speed of the cannon ball will be the same as the speed of the recoiling cannon
if the mass of the cannonball equals the mass of the cannon
the force of an apple hitting the ground depends upon
the speed of the apple just before it hits, the time of impact with the ground, whether or not the apple bounces , air resistance of the apple as it falls
When you jump off a step, you usually bend your knees as you reach the ground. By doing this, the time of the impact is about 10 times more what it would be in a stiff legged landing, and the average force on your body is reduced by
about 10 times
Recoil is noticeable if you throw a heavy ball while standing on roller skates. if instead you go through the motions of throwing the ball but hold onto it, your net recoil velocity will be
zero
A Karate expert executes a swift blow and splits a cement block with her hand
the forces on both the block and the experts hand have the same magnitude, the time of impact on both and the experts hand are the same the impulses on both the block and the experts hand have the same magnitude
A moving freight car runs into an identical car at rest on the track. The cars couple together. compared to the velocity of the first car before the collision the velocity of the combined cars after the collision is
one half as large
two gliders having the same mass and speed move toward each other on an air track and stick together. after the collision the velocity of the gliders is
zero
A piece of putty moving with 2 units of momentum strikes and sticks to a heavy bowling ball that is initially at rest. after the putty sticks to the ball, both are set in motion with a combined momentum that is
2 units
The force that accelerates a rocket into outer space is exerted on the rocket by
the exhausts gas
If all people, animals, trains, and trucks all over the world began to walk or run towards the east then
earth would spin a bit slower
Suppose an astronaut in outer space wished to toss a ball against a very massive and perfectly elastic concrete wall and catch it as it bounces back. If the ball is as massive as the astronaut then
the astronaut will never catch the first bounce
a table tennis ball moving forward with 5 units 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
5 units
Superman is at rest in space when he throws an asteroid that has more mass than he does. Which moves faster, Superman or the Asteroid?
Superman
A cannonball shot from a long barrel cannon travels faster than one shot from a short barrel because the cannonball receives a greater
Impulse
While roller skating Granny collides with her tiny grandson Chester who is at rest, Ignoring any friction effects, chesters speed after the collsion
he and granny make a bouncing collision, each going in the opposite direction
A small economy car(low mass) and a Limousine(high mass) are pushed from rest across a parking lot, equal distances with equal forces. The car that receives the greater impulse is the
Limousine
A 2-kg ball is thrown at 3 m/s what is the balls momentum
6 kg ms
A 4 kg ball has a momenutim of 20 kg ms what is the balls speed
5 ms
A ball is moving at 6 ms and has a momentum of 24 kg ms what is the balls mass
4 kg
In physics, work is defined as
e. force times distance
If you lift two loads up one story, how much work do you do compared to lifting just one load up one story?
d. twice as much
If you lift one load up two stories, how much work do you do compared to lifting one load up only one story?
d. twice as much
If Nellie Newton pushes an object with twice the force for twice the distance, she does
c. four times the work
The unit of work is the
c. joule
Power is defined as the
c. work done on an object divided by the time taken to do the work
The unit of power is the
e. watt
Potential energy is the energy an object has because of its
c. location
The amount of potential energy possessed by an elevated object is equal to
d. the work done in lifting it
Kinetic energy of an object is equal to
b. one half the product of its mass times its speed squared
How much farther will a car traveling at 100 km/s skid than the same car traveling at 50 km/s?
d. four times as far
An arrow in a bow has 70 J of potential energy. Assuming no loss of energy to heat, how much kinetic energy will it have after it has been shot?
d. 70 J
Energy is changed from one form to another with no net loss or gain.
c. Always true
As a pendulum swings back and forth
e. all of the above
When a car’s speed triples, its kinetic energy
d. increases by nine times
Rockets are launched from an airplane in the forward direction of motion. The kinetic energy of the airplane will be
c. decreased
A job is done slowly, and an identical job is done quickly. Both jobs require the same amount of work but different amounts of
b. power
Which requires more work: lifting a 70-kg sack vertically 2 meters or lifting a 35-kg sack vertically 4 meters?
c. both require the same amount of work
A ball is thrown into the air with 100 J of kinetic energy which is transformed to gravitational potential energy at the top of its trajectory. When it returns to its original level after encountering air resistance, its kinetic energy is
c. less than 100 J
An object that has kinetic energy must be
c. moving
An object that has kinetic energy must have
c. momentum
Which has greater kinetic energy, a car traveling at 30 km/h or a half-as-massive car traveling at 60 km/h?
a. the 60 km/h car
A person on a roof throws one ball downward and an identical ball upward at the same speed. The ball thrown downward hit the ground with 140 J of kinetic energy. Ignoring air friction, with how much kinetic energy does the second ball hit the ground
b. 140 J
An object at rest may have
a. energy
If an object has kinetic energy, then it also must have
c. momentum
If the velocity of a moving object doubles, then what else doubles?
c. momentum
All simple machines ideally work on the principle that
d. work input equals work output
About how efficient is a typical gasoline-burning car engine?
b. 30%
A small economy car )low mass) and a limousine (high mass) are pushed from rest across a parking lot, equal to distances with equal forces. The car that receives more kinetic energy is the
c. neither one-they receive the same amount of kinetic energy
A popular toy consists of an aligned row of identical elastic balls suspended by strings so they touch each other. When two balls on one end are elevated and released, they slam into the array of balls and two balls pop out the other side. If instead, one ball popped out with twice the speed, this would be a violation of the conservation of
b. energy
Consider molecules of hydrogen gas and molecules of heavier oxygen gas that have the same kinetic energy. The molecules with the greater speed are
a. hydrogen
How many joules of work are done on a box when a force of 25 N pushes at 3 m?
e. 75 J
How much power is required to do 40 J of work on an object in 5 seconds?
c. 8 W
How much work is done on a 60-N box of books that you carry horizontally across a 6-m room?
a. 0 J
How much work is done on a 20-N crate that you lift 2 m?
e. 40 J
How much power is expended if you lift a 60 N crate 10 meters in 1 second?
e. 600 W
Suppose a moving car has 3000 J of kinetic energy. If the car’s speed doubles, how much kinetic energy will it then have?
e. 12,000 J
It takes 8- J to push a large box 8 m across a floor. Assuming the push is in the same direction as the move, what is the magnitude of the force on the box?
b. 10 N
If Kelly the kater’s speed increases so he has three times the momentum, then his kinetic energy increases by
c. nine times
A 60-N object moves at 1 m/s. Its kinetic energy is
b. 30 J
Sue can easily lift a 45-N rock with the help of a lever. When she pushes down with 20 N of force, she lifts the rock 0.3 meters. How far does she move her arms to do this?
b. 0.7 m
Mechanical energy can be in the form of
c. both kinetic and potential energy
When a worker shovels coal into the furnace of a train engine, energy is released from the cool as heat. The heat is used to make steam, which is then used to turn the wheels of the engine. Living cells can also be thought of as machines. What biological process uses combustion to release energy from molecules so that cells can do work?
b. metabolism
If Earth rotated faster about its axis, your weight would
A. Decrease
B. Increase
C. Stay the same.
A. Decreases
Stunt motorcyclist Biker Pete rides his bike inside a futuristic rotation space station- a giant rotation donut- shaped structure in space. The normal support feels like weight to him. As he rides his bike in the same direction that the station rotates, the normal force.
A. Remains unaffected
B. Decreases
C. Increases
C. Increases
As the rotation speed of a space habitat increases, the weight of the people inside…
A. Stays the same
B. Increases
C. Decreases
B. Increases
Which has greater angular speed, a horse near the outside rail of the merry go round or a horse near the inside rail?
A. The outside horse
B. The inside horse
C. Neither- they both have the same angular speed
C. Neither- they both have the same angular speed
Earth rotates and revolves through space. Earth rotates about the ___, which is an ___ axis. Earth revolves about the ___, which is ___ axis.
A. sun, external, north/south pole, internal.
B. north/south pole, external, sun, internal.
C. north/south pole, internal, sun, external.
D. sun, internal, north/south pole, external.
C. north/south pole, internal, sun, external.
A race car travels in a circle with a constant speed. The net force on the race car…
A. Is zero because the race car is not accelerating.
B. Is directed towards the center of the curve.
C. Is directed forward in the direction of travel.
D. none of the above.
B. Is directed towards the center of the curve.
Tapered rims on a railroad train wheels enable to round curves without any wheels skidding. Consider a curve with the outer track is one part in 25 linger than the inner track. The wide part of the rim should have a diameter wider than the narrow part by at least one part to____.
A. 25
B. 50
C. 12.5
D. 2
A. 25
If you whirl a ball on the end of a string and the string suddenly breaks, the ball will….
A. Fly off, tangent to its circular path.
B. Fly directly toward you.
C. Spiral away from your hand.
D. Fly directly away from you.
E. Spiral in toward your hand.
A. Fly off, tangent to its circular path.
A person weighs less at the equator than at the poles. The reason for this has to do with the…
A. Spin of the Earth.
B. Influence of the sun, moon, and all of the planets.
C. Tidal bulges.
D. Higher temperatures at the equator, and the expansion of matter.
E. Too much thanksgiving dinner.
A. Spin of the earth.
Newbs Newton swings a rock into a circular path while holding an attached string overhead. The string makes a 45- degree angle to the vertical (compromising a “concial pendulum”). The centripetal force that holds the rock in its circular path is the….
A. Tension in the string.
B. Vertical component of the string tension.
C. Horizontal component of the String tension.
D. None of the above.
C. Horizontal component of the String tension.
Earth Rotates in a/ an_________direction.
A. Elliptical
B. Circular vector
C. Clockwise
D. Counter Clockwise
D. Counter Clockwise
When a railroad train rounds a banked track, the centripetal force needed comes not from friction, but from the…
A. Horizontal component of the normal force.
B. Normal force.
C. Vertical component of the normal force.
D. None of the above.
A. Horizontal component of normal force.
A space habitat is designed so that the variation in g between a person’s head and feet is less than 0.01 g. If the person is 2 m tall, then the radius of the habitat is…
A. 2000 m
B. 200 m
C. 20 m
D. more than 2000 m
B. 200 m
A vertical pole standing against a wall topples to the ground and the center of the pole has a speed of 26 m/s as it hits the ground. With what speed does the far end of the pole hit the ground?
A. 52 m/s
B. 26 m/s
C. 39 m/s
D. 13 m/s
A. 52 m/s
To weigh less in the Southern Hemisphere, you should go…
A. West
B. North
C. East
D. South
B. North
Nick Spacewalker hovers in space beside a rotating space station in outer space. Both he and the center of mass of the space station are at relative rest. If the space station is in Earth’s orbit, than Nick
A. may or may not be in Earth orbit.
B. is not in Earth’s orbit.
C. Is also in Earth’s orbit.
C. Is also in Earth’s orbit.
A game room in a rotating space habitat is located in a 0.25-g region. If a person can jump 0.5-m high in a 1-g region, how high can the same person jump in the game room?
A. 8 m
B. 4 m
C. 2 m
D. More than 8 m
E. 0.5 m
C. 2 m
Which of the following is not a unit of rotational speed?
A. Miles per hour
B. Revolutions per minute
C. Rotations per minute
D. Rotations per second
E. Revolutions per second
A. Miles Per Hour
The tangential speed of the outer rim of a ferris wheel is 30 m/s. What is the tangential speed of a position half- way from the center to the outer rim.
A. 20 m/s
B. 60 m/s
C. 15 m/s
D. 10 m/s
C. 15 m/s
People in the future may well live inside a rotating space structure that is more than 2 km in diameter. Inside the structure, people on the inside of the outer edge will experience 1 g while people halfway to the axis will experience
A. 1 g
B. 0 g
C. 1/4 g
D. 2 g
E. 1/2 g
E. 1/2 g
A rock whirled on the end of a string moves in a circle because…
A. Once the rock starts moving, that is its natural tendency.
B. The rock continually pulls on the string.
C. There is an inward force acting on the rock.
D. There is a force on the rock pulling it outward.
E. All of the above.
C. There is an inward force acting on the rock.
A possible space habitat of the future is a cylinder in space rotating about its long axis. What is the relative gravitational field along the axis of the habitat?
A. Three- Quarters G
B. Zero
C. One- Quarter G
D. One- Half G
E. G
B. Zero
“Centrifugal forces” are an apparent reality to observers in a reference frame that is …
A. At rest
B. An intertial reference frame
C. Moving at a constant velocity
D. Rotating
E. Bouncing
D. Rotating
You sit at the outer rim of a ferris wheel that rotates at 22 revolutions per minute (RPM). What would your rotational speed be if you were instead clinging to a position half- way from the center to the outer rim?
A. 11 RPM’S
B. 2 RPM’S
C. 44 RPM’s
D. 22 RPM’s
D. 22 RPM’S
What is the direction of the force that acs on clothes in the spin cycle of a washing machine?
A. Up
B. Down
C. Outward
D. Inward
D. Inward
Which has greater linear speed, a horse near the outside rail of a merry go round or a horse near the inside rail?
A.The outside horse
B. Neither- they both have the same speed
C. The inside horse
A. The outside horse
Stunt motorcyclist Biker Harry rides his bike inside a futuristic rotating space station- a giant rotating donut- shaped structure in space. The normal support force feels like weight to him. As he rides his bike in the opposite direction to the station’s rotation, the normal force…
A. Increases
B. Decreases
C. Remains the same
B. Decreases
The centripetal force exerted on stunt motorcyclist Biker Bruno while riding on the inner vertical surface of a circular track is
A. His weight
B. The normal force
C. Friction
D. None of the above
B. The normal force
At the outer edge of a rotating habitat, 130m from its center, the rotational acceleration is g. What is the rotational acceleration at a distance of 65 m from the center of the habitat.
A. 2x g
B. 1/3 g
C. 4x g
D. 1/2 g
D. 1/2 g
A worm rests on the bottom of a tin can that is being whirled horizontally on the end of a string. Since the worm, like the tin can, moves in a circle, there must be a force on it. What exerts this force?
A. Gravity
B. Your hand
C. The tin can
D. The String
E. There is no force acting on it.
C. The tin can
Where is the center of gravity of a softball bat located?
In the more massive end
When a wrench is slid spinning over a frictionless tabletop, its center of gravity follows
a regular straight-line path
An object will fall over if its center of gravity is
not over its area of support
When you carry a heavy load with one arm, why do you tend to hold your free arm away from your body?
to change the center of gravity of your body and the load
If an object is in unstable equilibrium, any displacement will
lower its center of gravity
If an object is in stable equilibrium, any displacement will
raise its center of gravity
If an object is in neutral equilibrium, any displacement will
neither raise nor lower its center of gravity
If you try to touch your toes while standing flat against a wall, you probably will fall over. The reason this happens is that
your center of gravity is not located directly above your support area
The center of mass of the solar system
varies as the planets move
The long heavy tail of a spider monkey enables the monkey to easily vary is
center of gravity
The center of mass of a human body is located at a point
that changes as a person bends over
An object thrown into the air with a spin rotates about its
center of gravity
A fish suspended in water is in what kind of equilibrium
neutral
A ball resting on the floor is in what kind of equilibrium
neutral
A picture hangs on a wall from a wire that is passed over a supporting nail. The picture is in stable equilibrium because
all of the above
Based on stability concepts, you would expect a very broad tree to have
a very broad root system
You push a table tennis ball beneath the surface of water in a glass of water. The center of gravity of the glass of water
rises
Torque is defined as
force times lever arm
Suppose you try loosening a nut with a wrench, and the nut doesn’t give at all. You increase your chance of success if you
all of the above
To turn a stubborn screw, it is best to use a screwdriver that has a
wide handle
At the health spa, Felix Flex finds that pulleys in the exercise machines are not circular, but are cams- oval-shaped pulleys. At different orientations, the cams provide different
both A and B (lengths of lever arms and forces required to produce a given torque)
Two people sit on a balanced seesaw. When one person leans toward the center of the seesaw, that person’s end of the seesaw will
rise
A meter stick is balanced at the 50.0 cm mark. You tie a 10.0N weight at the 15.0 cm mark. Where should a 30.0 N weight be placed so the meter stick will again be balanced?
61.7 cm mark
An object in motion with a constant force and no resistance will either travel in a straight line or travel
in a circle
Most females have a better ability to balance their bodies in motion compared to a male because
most females center of mass creates a rotational equilibrium