As the speed of a bicycle moving along a level, horizontal road changes from 2 m

Question

As the speed of a bicycle moving along a level, horizontal road changes from 2 m/s to 4 m/s, the bicycle's gravitational potential energy

• increases.
• decreases.
• remains the same.
• first increases then decreases.



The total mechanical energy of a system

• can never be negative.
• is either all kinetic energy or all potential energy.
• is constant.
• is equally divided between kinetic energy and potential energy.



A powerful machine does a lot of work in a __ amount of time.

• friction
• long
• short
• rate
• gravity



Which combination of units is equivalent to the unit for mechanical power?

• J x s
• J / s
• s / J



A ball is thrown upward. As the ball rises, its gravitational potential energy will

• decrease.
• increase.
• remain the same.
• first decrease then increase.



How much kinetic energy did 93.9-kg Usain Bolt have when he broke the Olympic 100-m dash record with a speed of 10.25 m/s?

Which equation would you use to solve this problem?

• (1/2)mv^2
• Fv
• W/t
• mgh
• mgh = (1/2)mv^2
• Fd



According to legend Isaac Newton “discovered” gravity when a 0.20 kg apple fell 7.0 m from a tree. How fast was it going when it hit Newton’s head?

Which equation would you use to solve this problem?

• Fd
• mgh
• Fv
• (1/2)mv^2
• W/t
• mgh = (1/2)mv^2



When a force causes an object to come to a stop, that force does

• positive work.
• negative work.
• no work.



As a sky diver falls to the ground,

• kinetic energy increases, gravitational energy decreases.
• kinetic energy stays constant.
• kinetic energy decreases, gravitational energy increases.



When an object is pushed or pulled, work is done against __.

• gravity
• short
• friction
• rate
• long



As the time needed to run up a flight of stairs decreases, the amount of work done against gravity

• decreases then increases.
• increases then decreases.
• decreases.
• remains the same.
• increases.




As the power rating of a machine is increased, the time required for the machine to do work

• decreases.
• decreases then increases.
• increases then decreases.
• increases.
• remains the same.



Energy is never lost. Eventually all forms of energy become

• gravitational energy.
• elastic energy.
• kinetic energy.
• thermal energy.


Allen pushes a box with a force of 10 N for a distance of 10 m. Bill lifts a 50 N box 2 m. Who did the most work?

• Allen
• Bill
• Both did the same amount of work.



How much gravitational potential energy did King Kong have at the top of the Empire State Building? King Kong had a mass of 25×106 kg. The Empire State Building is 381 m (1,250 feet) tall.

Which equation would you use to solve this problem?

• W/t
• Fv
• Fd
• (1/2)mv^2
• mgh = (1/2)mv^2
• mgh



As an object falls freely toward the Earth, the loss in gravitational potential energy is equal to its

• loss of height.
• gain in velocity.
• loss of mass.
• gain in kinetic energy.



A block is pulled along a smooth, level floor causing the block to accelerate. The energy gained by the block is equal to the

• force applied to the block.
• power developed by the block.
• distance the block is pulled.
• work done on the block.



If the total work done on an object is zero, then the object's kinetic energy

• is zero.
• remains the same.
• decreases.
• increases.



Power is the __ at which work is done.

• short
• gravity
• long
• friction
• rate



An object has gravitational potential energy due to __.

• vector
• height
• scalar
• constant
• in motion




In physics, a __ that causes the displacement of an object does work on the object.

Your response:



In 1985 in San Antonio, Texas, an entire hotel building was moved several blocks on thirty-six dollies. It took 284,200 N or force to move the building 352 m. How much work was done on the building?

Which equation would you use to solve this problem?

• (1/2)mv^2
• W/t
• mgh
• Fv
• Fd
• mgh = (1/2)mv^2



Which of the following is gravitational energy changing to kinetic energy?

• rolling up a hill
• object thrown into the air
• jumping into the air
• falling object



When an object is lifted, work is done against __.

• gravity
• rate
• long
• short
• friction


You are running up a flight of stairs. You have __.

• gravitational potential energy
• kinetic energy and gravitational potential energy.
• kinetic energy


Which of the following actions results in NO work done?

• holding an object stationary above the floor.
• pushing an object along the floor against friction.
• decreasing the speed of an object until it comes to rest.
• lifting an object from the floor to a table.




A bowling ball and a baseball are dropped from the same height at the same time. After free-falling for a few seconds, the balls will have different

• kinetic energies.
• accelerations.
• speeds.



An electric motor can do 10,000 J of work in 15 s. What is the power rating of the motor?

Which equation would you use to solve this problem?

• Fd
• mgh = (1/2)mv^2
• Fv
• mgh
• (1/2)mv^2
• W/t



Which of the following have the same unit?
1. work
2. power
3. kinetic energy

• 1 and 2
• 1 and 3
• 2 and 3



1 horsepower =

• 746 watts
• 446 watts
• 646 watts
• 546 watts



With all your might, you lift a 50-kg box 2.0 m. How much work do you do holding the box at 2.0 m?

• 0 J
• less than 100 J, but more than 0 J
• 100 J
• more than 100 J.


The "discovery" of the law of conservation of energy was given to

• Einstein.
• Galileo.
• Newton.
• Joule.




__ energy is energy associated with an object's motion.

Your response:



If the force on an object is perpendicular to the __ of the object, then no work is done on the object.

Your response:



In the SI system, work has a unit of __ times meter, or joule.

Your response:
blank answer



If the total work done on an object is positive, then the object's kinetic energy

• decreaes.
• increases.
• remains the same.
• is zero.



If you push twice as hard against the side of a building, the amount of work you do

• is cut in half.
• doubles.
• remains constant but not zero.
• remains constant at zero.




As a ball falls freely toward the Earth, its kinetic energy

• first decrease and then decrease.
• remains the same.
• increases.
• decreases.




You are walking through Lake Taylor's foyer. You have __.

• kinetic energy
• kinetic energy and gravitational potential energy.
• gravitational potential energy



As a simple pendulum swings from its lowest point to its highest point, the gravitational potential energy of the bob

• first increases then decreases.
• remains the same.
• increases.
• decreases.



When something is conserved, that something remains __.

• constant
• in motion
• vector
• scalar
• height




The work done to raise an object must result in an increase in the object's

• elastic potential energy.
• internal energy.
• kinetic energy.
• gravitational potential energy.




A student at the mall wants to go to a music shop on the 3rd floor of the mall. Stairs, escalator, or elevator...which one will do the least amount of work?

• escalator
• elevator
• All three will do the same amount of work.
• stairs


A wrecking ball is swinging toward a brick wall. At what point in the swing should the ball make contact with the wall to make collision with the greatest speed?

• half way between the highest point and the lowest point
• it does not matter
• the lowest point
• the highest point



Kinetic energy is energy associated with an object __.

• in motion
• scalar
• height
• vector
• constant



Engine A can haul 100 N at a speed of 2 m/s. Engine B can haul 200 N at a speed of 1 m/s. Which engine has more power?

• Engine A
• Engine B
• Both develop the same amount of power.



Which of the following is kinetic energy changing to gravitational energy?

• jumping into the air
• standing at the edge of a cliff
• falling object
• rolling down a hill



Can work be done on a system if there is no motion?

A Yes, since motion is only relative.
B No, since a system which is not moving has no energy.
C No, because of the way work is defined.
D Yes, if an outside force is provided.


The rate at which work is done is called __.

Your response:



Which combination of units is equivalent to the unit for mechanical work?

A N x m
B N / m
C m / N




As a bullet shot upward rises, the kinetic energy of the bullet

A decreases.
B increases.
C remains the same.
D first increases then decreases.


An engine moves a motorboat at a constant speed of 15 m/s. If the water offers a resistance of 6000 N, what is the power rating of this engine?

Which equation would you use to solve this problem?

A mgh = (1/2)mv^2
B (1/2)mv^2
C Fd
D mgh
E Fv
F W/t



One elevator goes up a given height in 10 seconds while another elevator does the same work in 5 seconds. Compared to the power rating of the first elevator, the power rating of the second elevator is

A the same.
B one-half as great.
C four times as great.
D twice as great.

Explanation / Answer

A ball is thrown upward. As the ball rises, its gravitational potential energy will ->increases How much kinetic energy did 93.9-kg Usain Bolt have when he broke the Olympic 100-m dash record with a speed of 10.25 m/s? -> (1/2)mv^2 According to legend Isaac Newton “discovered” gravity when a 0.20 kg apple fell 7.0 m from a tree. How fast was it going when it hit Newton’s head? -> mgh = (1/2)mv^2 When a force causes an object to come to a stop, that force does -> negative work As a sky diver falls to the ground, ->• kinetic energy increases, gravitational energy decreases. When an object is pushed or pulled, work is done against __. -> friction As the time needed to run up a flight of stairs decreases, the amount of work done against gravity ->• remains the same. As the power rating of a machine is increased, the time required for the machine to do work ->decreases Energy is never lost. Eventually all forms of energy become -> thermal energy Allen pushes a box with a force of 10 N for a distance of 10 m. Bill lifts a 50 N box 2 m. Who did the most work? ->• Both did the same amount of work How much gravitational potential energy did King Kong have at the top of the Empire State Building? King Kong had a mass of 25×106 kg. The Empire State Building is 381 m (1,250 feet) tall How much gravitational potential energy did King Kong have at the top of the Empire State Building? King Kong had a mass of 25×106 kg. The Empire State Building is 381 m (1,250 feet) tall -> mgh As an object falls freely toward the Earth, the loss in gravitational potential energy is equal to its -> gain in kinetic energy A block is pulled along a smooth, level floor causing the block to accelerate. The energy gained by the block is equal to the • work done on the block. If the total work done on an object is zero, then the object's kinetic energy • is zero. Power is the __ at which work is done. • rate An object has gravitational potential energy due to __. • height In physics, a __ that causes the displacement of an object does work on the object. Your response: -> Force In 1985 in San Antonio, Texas, an entire hotel building was moved several blocks on thirty-six dollies. It took 284,200 N or force to move the building 352 m. How much work was done on the building? Which equation would you use to solve this problem? • Fd Which of the following is gravitational energy changing to kinetic energy? • falling object When an object is lifted, work is done against __. • gravity You are running up a flight of stairs. You have __. • kinetic energy and gravitational potential energy. Which of the following actions results in NO work done? • holding an object stationary above the floor. A bowling ball and a baseball are dropped from the same height at the same time. After free-falling for a few seconds, the balls will have different • kinetic energies. An electric motor can do 10,000 J of work in 15 s. What is the power rating of the motor? Which equation would you use to solve this problem? • W/t Which of the following have the same unit? 1. work 2. power 3. kinetic energy • 1 and 3 1 horsepower = • 746 watts With all your might, you lift a 50-kg box 2.0 m. How much work do you do holding the box at 2.0 m? • 100 J The "discovery" of the law of conservation of energy was given to • Joule. __ energy is energy associated with an object's motion. Your response: ---> Kinetic energy If the force on an object is perpendicular to the __ of the object, then no work is done on the object. Your response: ---> displacement or direction of motion In the SI system, work has a unit of __ times meter, or joule. Your response: - > Force If the total work done on an object is positive, then the object's kinetic energy • increases. If you push twice as hard against the side of a building, the amount of work you do • remains constant at zero. As a ball falls freely toward the Earth, its kinetic energy • increases. You are walking through Lake Taylor's foyer. You have __. • kinetic energy and gravitational potential energy. As a simple pendulum swings from its lowest point to its highest point, the gravitational potential energy of the bob • increases. When something is conserved, that something remains __. • constant The work done to raise an object must result in an increase in the object's • gravitational potential energy.

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