Work, Power and Energy

1. Work, Power and Energy

4. And Your Host... Ms. G!

5. Work

6. Power

7. Energy

8. Mechanical Energy

9. Units and Formulas

10. Machines

12. 1 ~ $100 Question If you push for an hour against a stationary wall, how much work do you do?

13. 1 ~ $100 Answer None- the wall doesn’t move, so there’s no distance

14. 1 ~ $200 Question If you push an object just as far while applying twice the amount of force, how much work do you do?

15. 1 ~ $200 Answer Twice the amount of work

16. 1 ~ $300 Question While impulse involves the time that a force acts, work involves what?

17. 1 ~ $300 Answer The distance the force acts

18. 1 ~ $400 Question A 1000kg car and a 2000kg car are hosted the same distance in a gas station. Does raising the more massive car require more work? If so, how much?

19. 1 ~ $400 Answer It requires twice as much work because it requires twice the force to lift the heavier car

20. 1 ~ $500 Question The super weight lifter of the world tries to show off and carry a 60N weight across the stage while its over his head. The stage is 15m. How much work is being done?

21. 1 ~ $500 Answer None- the force that is exerted on the barbell is not the force that moves the barbell across the stage

22. 2 ~ $100 Question A job is done slowly while an identical job is done quickly. Both jobs require the same amount of work, but different amounts of what?

23. 2 ~ $100 Answer Power

24. 2 ~ $200 Question Power is how _____ _____ is done

25. 2 ~ $200 Answer quickly work

26. 2 ~ $300 Question Exert 100 J in 50 s and your power output is…

27. 2 ~ $300 Answer 2 Watts

28. 2 ~ $400 Question Using 1000J of work, a toy elevator is raised from the ground floor to the second floor in 20 s. How much power does the elevator use?

29. 2 ~ $400 Answer 50 Watts

30. 2 ~ $500 Question A horse pulls a plow across a field in 60 seconds. If 10,000 Watts of power is used then how much work is performed by the horse?

31. 2 ~ $500 Answer It takes 600,000 J

32. 3 ~ $100 Question Energy is the ability to do ______

33. 3 ~ $100 Answer work

34. 3 ~ $200 Question Name at least three types of energy

35. 3 ~ $200 Answer Examples- heat, light, sound, radioactivity, mechanical energy, etc.

36. 3 ~ $300 Question Explain some of the properties of energy using the law of conservation of energy

37. 3 ~ $300 Answer Energy cannot be created or destroyed, only transferred or transformed

38. 3 ~ $400 Question The work energy theorem shows the relationship between what two things?

39. 3 ~ $400 Answer Work and kinetic energy

40. 3 ~ $500 Question Use the work/energy theorem to explain why a force can change the energy of an object

41. 3 ~ $500 Answer Work is force times distance, so if a force changes the work of the object, then the work will change the kinetic energy of the object according to the work/energy theorem

42. 4 ~ $100 Question What are the two types of mechanical energy?

43. 4 ~ $100 Answer Potential and kinetic energy

44. 4 ~ $200 Question An object is raised above the ground gaining a certain amount of potential energy. If the same object is raised twice as high, it games how much potential energy?

45. 4 ~ $200 Answer Twice as much

46. 4 ~ $300 Question An object that has potential energy may have this energy because of the object’s ________.

47. 4 ~ $300 Answer Position (height)

48. 4 ~ $400 Question A bow is drawn so that it has 40 J of potential energy. When fired, the arrow will have how much kinetic energy? Why?

49. 4 ~ $400 Answer 40 J because of the law of conservation of energy

50. 4 ~ $500 Question A car moves 4 times as fast as another identical car. Compared to the slower car, the faster car has how much kinetic energy? Why?