Short Answer
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1.
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C5 Work and Energy
Explain the
scientific meaning of work.
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2.
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In the following sentence, is the everyday meaning or the scientific meaning of
work intended?
A student works on a term paper.
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3.
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In the following sentence, is the everyday meaning or the scientific meaning of
work intended?
A coach does work on the bleachers by moving them into place before the basketball
game.
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4.
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In the following sentence, is the everyday meaning or the scientific meaning of
work intended?
A bulldozer does work lifting a load.
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5.
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In the following sentence, is the everyday meaning or the scientific meaning of
work intended?
A clerk works overtime on Saturdays.
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6.
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How is work related to force and displacement?
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7.
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What formula can be used to calculate work if the force acts at an angle to the
displacement?
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8.
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Name the two SI units for work.
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9.
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Is work a vector quantity or a scalar quantity?
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10.
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A child pulls a toy across the floor. Is the work done on the toy positive,
negative, or zero?
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11.
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Air exerts a force on a leaf as it falls from a tree to Earth. Is the work done
on the leaf positive, negative, or zero?
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A car travels at a speed of 25 m/s on a flat stretch of road. The driver must
maintain pressure on the accelerator to keep the car moving at this speed.
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12.
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Are any forces doing work on the car? Explain your answer.
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13.
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What is the net work done on the car over a distance of 250 m?
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14.
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The car’s engine is doing work on the car, yet the kinetic energy of the
car is not changing. What is happening to the energy supplied by the engine?
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15.
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What form of energy is associated with the position of an object in
Earth’s gravitational field?
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16.
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What form of energy is stored in any stretched or compressed object?
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17.
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Is kinetic energy a vector quantity or a scalar quantity?
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18.
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State, in words, the work-kinetic energy theorem.
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19.
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Negative work is done on a moving object. How does the kinetic energy of the
object change?
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20.
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Describe the relationship between kinetic energy and gravitational potential
energy during the free fall of a pencil from a desk.
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21.
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A pocket watch contains a long, spiral piece of metal which is coiled tightly as
the watch is wound. What form of potential energy is involved in winding a pocket watch?
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22.
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An object is lowered into a deep hole in the ground. How does the potential
energy of the object change?
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23.
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You are analyzing the flight of a projectile through the air. What assumption do
you have to make in order to use conservation of mechanical energy in your analysis?
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24.
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A ski jumper has 1.2 ´ 10  J of potential energy at the top of the ski jump. The friction on the jump slope is
small, but not negligible. What can you conclude about the ski jumper’s kinetic energy at the
bottom of the jump? Explain your answer.
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25.
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What quantity is the sum of the kinetic energy and all forms of potential energy
in a system?
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26.
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List three different forms of mechanical energy.
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27.
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Write a symbolic expression of the conservation of mechanical energy.
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28.
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Write an equation that expresses the conservation of mechanical energy in a
system where the only forms of mechanical energy are kinetic energy and gravitational potential
energy.
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29.
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Write an equation that expresses the conservation of mechanical energy in a
system where the only forms of mechanical energy are kinetic energy and elastic potential
energy.
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30.
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Write an equation that expresses the conservation of mechanical energy in a
system that involves kinetic energy, gravitational potential energy, and elastic potential
energy.
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31.
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A pendulum is raised 1.5 cm and allowed to fall. If air resistance is
negligible, how high will the pendulum rise on the other side?
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32.
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A child does 5.0 J of work on a spring while loading a ball into a spring-loaded
toy gun. If mechanical energy is conserved, what will be the kinetic energy of the ball when it
leaves the gun?
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33.
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Explain how energy, time, and power are related.
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34.
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How are work and power related?
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35.
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Is power a vector quantity or a scalar quantity?
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36.
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Show how the alternative definition of power can be derived by
substituting the definitions of work and speed into the standard definition of
power,  .
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37.
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What does the wattage of a light bulb indicate?
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38.
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How is a machine’s power rating related to its rate of doing work on an
object?
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39.
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In terms of energy, what occurs when a machine does work on an object?
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40.
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Which motor performs more work in the same amount of time—a 10 kW motor or
a 20 kW motor? How much more work can it do?
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41.
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What is the kinetic energy of a 1.5 ´
10  kg car traveling at 25 m/s?
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42.
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C6 Momentum and Collisions
Write
the equation for momentum, first using symbols for the variables, then using words for the
variables.
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43.
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As a bullet travels through the air, it slows down due to air resistance. How
does the bullet’s momentum change as a result?
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