Reading Questions 9.1††††††††††††††††††††††††††††††††††††††††††††††††† Name ____________________________________

Work, Power, and Machines pp. 284-290†††††††

 

  1. Write the four objectives of this section.
  2. When is work done?
  3. How is work calculated?
  4. Why donít you do work when you try to lift a car?
  5. Is the weight lifter in Figure 9-1 doing work?
  6. What are the three units for work?
  7. How big is a J?
  8. Look at the practice hint, how do you get force, when it gives you kilograms?
  9. What is power?
  10. Why does running up the stairs use more power than walking up thes tairs?
  11. What units is power measured in?
  12. What is horsepower?
  13. How does a jack make it easier to lift a car?
  14. What two ways can machine make doing work easier?
  15. Compare the amount of work done in Figure 9-3A and 9-3B.
  16. Compare the amount of force needed in Figure 9-3A and 9-3B.
  17. How do a car jack and a ramp make doing work easier?
  18. What is mechanical advantage?
  19. How is mechanical advantage calculated?
  20. What does it mean if a machine has a mechanical advantage greater than one?
  21. What does it mean if a machine has a mechanical advantage less than one?