Name: __________________________________________ Period: _____ Date: _________

Dekalb Reads Assignment 9.4

Conversion of Energy

Read pages 306-312 and answer the following questions
  1. What is the most important part of the coaster ride?
  2. Where does the energy required for the entire coaster ride come from?
  3. Write down the different forms of energy in to which the Gravitational Potential Energy is transformed during roller coaster ride?
  4. When is the potential energy of the roller coaster car changed to kinetic energy?
  5. At which point of the roller coaster, the car has no more PE?
  6. Why the can not climb the hill taller than the first one?
  7. In the example given on page 308, what happens as the ball rises higher?
  8. The ball keeps rising until _________________.
  9. What happens as the ball falls down again?
  10. What does the tennis player do when she throws the ball down?
  11. What happens to the K.E of the ball when it hits the ground?
  12. What happens to the elastic potential energy when the ball bounces off?
  13. When a ball bounces on the ground, not all of the KE changes to elastic potential energy. Why?
  14. What happens with each bounce of the ball?
  15. Why does the total mechanical energy of a car on a roller coaster decrease?
  16. Write down the law of conservation of energy.
  17. Whenever the total energy in a system increases it must be due to _______________________ .
  18. Mechanical energy can be changed to non mechanical energy due to ___________________ .
  19. Does the energy disappear? What happens to it?
  20. What is a closed system?
  21. What is an open system?
  22. What kind of system is earth?
  23. Is your body an open or closed system? (Think)
  24. Is all of the work done by a machine useful?
  25. Why only some of the work done by a machine is applied to the task at hand?
  26. Which is not a desired effect of work available to lift the sail?
  27. Define efficiency.
  28. Write down the equation of efficiency.
  29. "No machine has 100% efficiency". Why?
  30. Can the work output of a machine be equal to or exceed work input?
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