CHAPTER 15 Assessment

Reviewing Content

Choose the letter that best answers the question or completes the statement.

1. The energy of a moving` object is

   1. kinetic energy.

   2. potential energy.

   3. chemical energy.

   4. nuclear energy.

2. If the speed of an object doubles, its kinetic energy

   1. doubles.

   2. quadruples.

   3. stays the same.

   4. is halved.

3. An example of an object having elastic potential energy is

   1. a stretched spring.

   2. books on a shelf.

   3. a moving arrow.

   4. a falling oyster.

4. An example of electromagnetic energy is

   1. a falling rock.

   2. a stretched spring.

   3. a speeding train.

   4. sunlight.

5. Energy stored in the bonds between atoms is called

   1. kinetic energy.

   2. mechanical energy.

   3. chemical energy.

   4. thermal energy.

6. Mechanical energy is

   1. found in machinery only.

   2. usually measured at the atomic level.

   3. the sum of the chemical and thermal energy of an object.

   4. the sum of the kinetic and potential energy of an object.

7. An example of the conversion of gravitational potential energy into kinetic energy is

   1. a falling raindrop.

   2. a gasoline-powered engine.

   3. striking a match.

   4. a hockey puck sliding on ice.

8. The law of conservation of energy states that

   1. energy cannot be converted from one form to another.

   2. energy cannot be created or destroyed.

   3. energy resources must be used efficiently.

   4. energy is constantly being lost to friction.

9. Which of the following energy resources accounts for most of the world's present energy use?

   1. uranium

   2. solar energy

   3. fossil fuels

   4. wind energy

10. Most renewable energy originates from

    1. fossil fuels.

    2. the ground.

    3. the sun.

    4. uranium.

Understanding Concepts

11. What is energy?

12. How are kinetic energy and potential energy different?

13. How does the potential energy of an object change when its height is tripled?

14. Look at the graphs below. One of the graphs is a plot of kinetic energy vs. mass for a set of objects with different masses, all moving at the same speed. The other graph is a plot of kinetic energy vs. speed for a set of objects with the same mass, all moving at different speeds. Identify each graph and explain how can you tell which graph is which.

    d

15. What happens to the atoms of an object if its thermal energy is increased?

16. Explain the energy conversions that occur as a basketball falls, hits the ground, and bounces back up. Ignore frictional forces.

17. What force is acting when the kinetic energy of a moving object is converted into thermal energy?

18. Explain how energy is converted as a pendulum swings.

19. Is mechanical energy always conserved? Explain why or why not.

20. Explain the meaning and the importance of the formula E = mc ².

21. Why are coal, oil, and natural gas considered to be nonrenewable energy resources?

22. What is the source of geothermal energy?

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