Name: 

Please Note:  This exam has explanations to the answers, and is for practice.  To take the real exam and submit your score to Mr. Morrison, click here:  Online Energy Practice Exam.

Energy Exam Study Guide 



Multiple Choice
Identify the choice that best completes the statement or answers the question.
 

 1. 

In physics, work is defined as
a.
force times time.
b.
force divided by distance.
c.
distance divided by time.
d.
force divided by time.
e.
force times distance.
 

 2. 

f you lift two loads up one story, how much work do you do compared to lifting just one load up one story?
a.
One quarter as much
b.
One half as much
c.
The same amount
d.
Twice as much
e.
Four times as much
 

 3. 

If you lift one load up two stories, how much work do you do compared to lifting one load up only one story?
a.
One quarter as much
b.
One half as much
c.
The same amount
d.
Twice as much
e.
Four times as much
 

 4. 

If Nellie Newton pushes an object with twice the force for twice the distance, she does
a.
twice the work.
b.
the same work.
c.
four times the work.
d.
eight times the work.
 

 5. 

The unit of work is the
a.
watt.
b.
meter.
c.
joule.
d.
newton.
e.
second.
 

 6. 

Power is defined as the
a.
force on an object divided by the time the force acts.
b.
work done times the time taken to do that work.
c.
work done on an object divided by the time taken to do the work.
d.
distance divided by the time taken to move that distance.
e.
force on an object times the distance the object moves.
 

 7. 

The unit of power is the
a.
newton.
b.
meter.
c.
joule.
d.
second.
e.
watt.
 

 8. 

Potential energy is the energy an object has because of its
a.
density.
b.
size.
c.
location.
d.
speed.
e.
temperature.
 

 9. 

The amount of potential energy possessed by an elevated object is equal to
a.
the power used to lift it.
b.
the distance it is lifted.
c.
the force needed to lift it.
d.
the work done in lifting it.
e.
the value of the acceleration due to gravity.
 

 10. 

Kinetic energy of an object is equal to
a.
its mass multiplied by its acceleration squared.
b.
one half the product of its mass times its speed squared.
c.
its mass multiplied by its speed.
d.
one half the product of its mass times its speed.
e.
its mass multiplied by its acceleration.
 

 11. 

How much farther will a car traveling at 100 km/s skid than the same car traveling at 50 km/s?
a.
Half as far.
b.
The same distance.
c.
Twice as far.
d.
Four times as far.
e.
Five times as far.
 

 12. 

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?
a.
0 J
b.
35 J
c.
50 J
d.
70 J
e.
140 J
 

 13. 

Energy is changed from one form to another with no net loss or gain.
a.
Sometimes true
b.
Always false
c.
Always true
 

 14. 

As a pendulum swings back and forth
a.
at the end points of its swing, its energy is all potential.
b.
at the lowest part of its swing, its energy is all kinetic.
c.
kinetic energy is transformed into potential energy.
d.
potential energy is transformed into kinetic energy.
e.
all of the above
 

 15. 

When a car’s speed triples, its kinetic energy
a.
remains the same.
b.
triples.
c.
increases by four times.
d.
increases by nine times.
e.
none of the above
 

 16. 

A woman can lift barrels a vertical distance of 1 meter or can roll them up a 2-meter long ramp to the same elevation. If she uses the ramp, the applied force required is
a.
mc016-2.jpg as much.
b.
mc016-3.jpg as much.
c.
the same amount.
d.
2 times as much.
e.
4 times as much.
 

 17. 

A job is done slowly, and an identical job is done quickly. Both jobs require the same amount of work but different amounts of
a.
energy.
b.
power.
c.
both A and B
d.
none of the above
 

 18. 

Which requires more work: lifting a 70-kg sack vertically 2 meters or lifting a 35-kg sack vertically 4 meters?
a.
Lifting the 70 kg sack
b.
Lifting the 35 kg sack
c.
Both require the same amount of work.
 

 19. 

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
a.
100 J.
b.
more than 100 J.
c.
less than 100 J.
d.
Not enough information given.
 

 20. 

An object that has kinetic energy must be
a.
at rest.
b.
falling.
c.
moving.
d.
elevated.
 

 21. 

An object that has kinetic energy must have
a.
acceleration.
b.
a force applied to maintain it.
c.
momentum.
d.
none of the above
 

 22. 

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
b.
Both have the same kinetic energy.
c.
The 30 km/h car
 

 23. 

An object at rest may have
a.
energy.
b.
speed.
c.
velocity.
d.
momentum.
e.
none of the above
 

 24. 

If the velocity of a moving object doubles, then what else doubles?
a.
acceleration.
b.
kinetic energy.
c.
momentum.
d.
all of the above
e.
none of the above
 

 25. 

The ratio of output force to input force of a simple machine is called the
a.
fulcrum.
b.
efficiency.
c.
pivot point.
d.
lever arm.
e.
mechanical advantage.
 

 26. 

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.
b.
Both have the same speed.
c.
oxygen.
 

 27. 

How much power is required to do 40 J of work on an object in 5 seconds?
a.
0 W
b.
5 W
c.
8 W
d.
40 W
e.
200 W
 

 28. 

How much work is done on a 20-N crate that you lift 2 m?
a.
0 J
b.
1 J
c.
2 J
d.
20 J
e.
40 J
 

 29. 

How much power is expended if you lift a 60 N crate 10 meters in 1 second?
a.
0 W
b.
6 W
c.
10 W
d.
60 W
e.
600 W
 

 30. 

Suppose a moving car has 3000 J of kinetic energy. If the car's speed doubles, how much kinetic energy will it then have?
a.
1000 J
b.
1500 J
c.
3000 J
d.
6000 J
e.
12,000 J
 

 31. 

If Kelly the skater's speed increases so he has three times the momentum, then his kinetic energy increases by
a.
one third times.
b.
three times.
c.
nine times.
d.
none of the above (KE remains the same).
 

 32. 

A 60-N object moves at 1 m/s. Its kinetic energy is
a.
1 J.
b.
3 J.
c.
60 J.
d.
more than 60 J.
 

True/False
Indicate whether the statement is true or false.
 

 33. 

In physics, the amount of work done on an object is the product of the force exerted on the object times the time the object moves.
 

 34. 

The unit of work is called the joule.
 

 35. 

The rate at which work is done is called energy.
 

 36. 

The unit of power is the watt.
 

 37. 

The rate at which work is done is called power.
 

 38. 

The energy an object has by virtue of its location is its potential energy.
 

 39. 

The energy an object has by virtue of its motion is its kinetic energy.
 

 40. 

When we carry an object across a room, without lifting it or setting it down, we do no physical work on it.
 

 41. 

More power is needed to carry a heavy suitcase slowly up a flight of stairs than to carry the suitcase quickly up the same flight of stairs.
 

 42. 

Energy transforms from one form to another with no net loss or gain.
 

Essay
 

 43. 

You do work on something when you lift it against gravity. How does this work relate to gravitational potential energy? If the lifted object is released, what becomes of this energy? Be sure to define all terms that you use.
 

 44. 

Discuss how energy conservation applies to a pendulum. Where is potential energy the most? The least? Where is kinetic energy the most? The least? Where is it moving the fastest? Stopped?
 

Problem
 

 45. 

What is the work done in lifting 60 kg of blocks to a height of 20 m?
 

 46. 

A toy cart moves with a kinetic energy of 10 J. If its speed is doubled, what will its kinetic energy be?
 

 47. 

In raising a 3000-N piano with a pulley system, it is noted that for every 2 m of rope pulled down, the piano rises 0.2 m. Ideally, what force is needed to lift the piano?
 

 48. 

A car traveling at 50 km/h will skid 20 m when its brakes are locked. If the same car is traveling at 150 km/h, what will be its skidding distance?
 

 49. 

A 30-kg girl runs up the staircase to a floor 5 m higher in 8 seconds. What is her power output?
 

 50. 

At what height does a 1000-kg mass have a potential energy of 1 J relative to the ground?
 

 51. 

The 4.0-kg head of an ax is moving at 4.0 m/s when it strikes a log and penetrates 0.01 m into the log. What is the average force the blade exerts on the log?
 

 52. 

An anvil hanging vertically from a long rope in a barn is pulled to the side and raised like a pendulum 1.60 m above its equilibrium position. It then swings to its lowermost point where the rope is cut by a sharp blade. The anvil then has a horizontal velocity with which it sails across the barn and hits the floor, 10.0 m below. How far horizontally along the floor will the anvil land?
 



 
Check Your Work     Start Over