Multiple Choice Identify the choice that best completes the
statement or answers the question.
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1
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An arrow in a bow has 90 J of potential energy. Assuming no loss of energy to
heat, how much kinetic energy will it have after it has been shot?
a. | 180 J | b. | 45 J | c. | 70
J | d. | 0 J | e. | 90 J |
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2
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The unit of power is the
a. | meter. | b. | watt. | c. | newton. | d. | second. | e. | joule. |
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3
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If Nellie Newton pushes an object with twice the force for twice the distance,
she does
a. | twice the work. | b. | eight times the work. | c. | the same
work. | d. | four times the work. |
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4
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A ball is thrown into the air with 120 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. | less than 120 J. | b. | more than 120 J. | c. | 120
J. | d. | Not enough information given. |
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5
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Energy is changed from one form to another with no net loss or gain.
a. | Sometimes true | b. | Always true | c. | Always
false |
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6
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A 90-N object moves at 1 m/s. Its kinetic energy is
a. | 90 J. | b. | 1 J. | c. | more than 90
J. | d. | 4.5 J. |
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7
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The units for energy are
a. | joules | b. | watts | c. | newtons | d. | meters |
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8
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An object that has kinetic energy must be
a. | elevated. | b. | moving. | c. | at
rest. | d. | falling. |
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9
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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 |
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10
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A heavy object and a light object are released from rest at the same height and
time in a vacuum. As they fall, they have equal
a. | energies. | b. | momenta. | c. | weights. | d. | all of the above | e. | none of the
above |
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11
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A 4.0-kilogram mass is moving with a speed of 2.0m/s. What is the
kinetic energy of the mass?
a. | 6.0 J | b. | 16.0 J | c. | 8.0
J | d. | 4.0 J |
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12
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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 |
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13
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How many joules of work are done on a box when a force of 45 N pushes it 7
m?
a. | 315 J | b. | 7 J | c. | 45
J | d. | 6 J | e. | 1 J |
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14
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An object at rest may have
a. | velocity. | b. | speed. | c. | momentum. | d. | energy. | e. | none of the
above |
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15
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How much work is done on a 70-N object that you lift 6 m?
a. | 1 J | b. | 70 J | c. | 420
J | d. | 0 J | e. | 6 J |
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16
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The ratio of output force to input force of a simple machine is called the
a. | efficiency. | b. | pivot point. | c. | lever
arm. | d. | fulcrum. | e. | mechanical
advantage. |
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17
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Three objects move with a velocity of 3 m/s. What is the total kinetic energy of the system?
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18
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The unit of work is the
a. | second. | b. | meter. | c. | watt. | d. | joule. | e. | newton. |
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19
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Potential energy is the energy an object has because of its
a. | speed. | b. | density. | c. | location. | d. | size. | e. | temperature. |
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20
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When a car’s speed triples, its kinetic energy
a. | triples. | b. | increases by nine times. | c. | remains the
same. | d. | increases by four times. | e. | none of the
above |
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21
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A 4.0-kg concrete block falls to the ground from a 3-m-high roof. What is the
approximate kinetic energy of the concrete block just before it touches the ground?
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22
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The amount of potential energy possessed by an elevated object is equal to
a. | the distance it is lifted. | b. | the power used to lift it. | c. | the value of the
acceleration due to gravity. | d. | the work done in lifting
it. | e. | the force needed to lift it. |
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23
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In physics, work is defined as
a. | force divided by time. | b. | force times distance. | c. | distance divided by
time. | d. | force times time. | e. | force divided by
distance. |
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24
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Power is defined as the
a. | distance divided by the time taken to move that distance. | b. | force on an object
times the distance the object moves. | c. | force on an object divided by the time the
force acts. | d. | work done times the time taken to do that work. | e. | work done on an
object divided by the time taken to do the work. |
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25
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How much power is expended if you lift a 40 N crate 8 meters in 1 second?
a. | 8 W | b. | 320 W | c. | 5
W | d. | 0 W | e. | 40 W |
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26
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A hydraulic lift used at an automotive repair shop raises a 1500-kilogram car
one meters off of the ground. What is the potential energy given to the car?
a. | 15,000 J | b. | 1500 J | c. | 7,500
J | d. | 750 J |
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27
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As an object falls, its potential energy
a. | increases | b. | stays constant | c. | cannot be
determined | d. | decreases |
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28
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Which requires more work: lifting a 50-kg sack vertically 4 meters or lifting a
25-kg sack vertically 8 meters?
a. | Lifting the 50 kg sack | b. | Lifting the 25 kg sack | c. | Both require the
same amount of work. |
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29
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How much work is done on a 10-N rock that you carry horizontally across a 8-m
room?
a. | 80 J | b. | 8 J | c. | 0
J | d. | 10 J | e. | 1 J |
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30
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Kinetic energy of an object is equal to
a. | its mass multiplied by its speed. | b. | one half the product of its mass times its
speed squared. | c. | one half the product of its mass times its speed. | d. | its mass multiplied
by its acceleration. | e. | its mass multiplied by its acceleration
squared. |
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