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General Physics
Chapter 8 Review Assignment
ANSWERS
Fill-In-the-Blank
1. Work_______ is defined as force time distance.
2. If you lift two loads up one story, you will do __more_____ work than if you lift
one load up one story.
3. If you lift one load up two stories, you will do _____more____ work than if you
lift one load up one story.
4. The unit of work in SI base units is _kgm2/s2___. This is also called a _Joule__.
5. Power is defined as _work done divided by time interval____________________.
6. The unit of power in SI base units is _kgm2/s3__. This is also called a Watt____.
7. The unit of energy in SI base units is __ kgm2/s2_________. This is also called a
__Joule_.
8. The energy an object has due to its position is called (gravitational) potential
energy
9. The energy an object has due to motion is called _kinetic energy__.
10. The amount of work done to lift an object vertically is the same as the amount of
_gravitational potential energy_____________________________ it has.
11. The kinetic energy an object has is directly proportional to the square if its
_velocity_.
12. The amount of work done on a moving object is equal to its change in _kinetic
energy.
13. A bullet in a gun has 25 J of potential energy. It will then have _25___J of kinetic
energy when it is shot.
14. As a pendulum swings back and forth potential____energy is converted into
___kinetic_______ energy.
15. It takes _more_____distance to stop a fast moving car than it does to stop the
same car that is moving more slowly.
16. An object that has kinetic energy must be _moving_____.
Problem Solving
17. How much work is done in lifting 75 kg of books to a height of 3.5 m? 2.6 x 103J
18. A wagon is pushed 5.2 m across a floor by a 2.5N net force. By how much does
its kinetic energy change? 13 J
19. An 85.5 kg sledder (including sled) going downhill had a kinetic energy of 9.65 x
105 J. How fast was he going? 1.50 x 102 m/s
20. A pole vaulter with a mass of 68.5 kg jumped a vertical distance of 3.95 m. How
much gravitational potential energy did he have at the top of his jump?2.65 x 103J
21. Goofy is at the top of the Matterhorn, an elevation of 44.8 m. He slides down the
Matterhorn. How fast is he going at the bottom of the Matterhorn? 2.96 x 101m /s
22. A Navy ship generates 4.65 x 107 W of power. How much work can this ship do
in 5.75 hours? 9.63 x 1011 J