Force and Work - Jackie

C. 2W

8. Exert 100 J in 50s and your power output is

A. At all

1. If you push for an hour against a stationary wall, you will do no work

E. Twice as much

10. When an object is lifted 10m, it gains a certain amount of potential energy. If the same object is lifted 20m, its potential energy gain is

A. Twice as much work

11. A 1000-kg car and a 2000-kg car are hoisted the same distance in a gas station. Raising the more massive car requires

A. Moving

12. An object that has kinetic energy must be

C. Location

13. An object that has potential energy may have this energy because of its

B. 40 J

14. A bow is drawn so that it has 40 j of potential energy. When fired, the arrow will ideally have a kinetic energy of

A. Work B. Distance C. Time D. A&C ✓✓✓✓✓✓

19. What determines power?

A. Twice as much work

2. If you push an object twice as far while applying the same force, you do

B. Work

20. F(D) = is the formula for?

A. Gain force B. Increase distance C. Increase speed D. All of the above ✓✓✓✓✓✓

21. First class levers may

A. 1st

22. What class lever is your arm?

B. Distance

23. We're using a second-class lever what will you gain?

A. 1st

24. What kind of lever is a small child's teeter-totter?

B. Wedge

25. What type of machine is an axe blade?

B. Work

26. The result of the exertion of a force through a distance is?

A. Twice as much work

3. If you push an object just as far while applying twice the force, you do

D. Fulcrum

30. The point on which a lever is supported and free to rotate is called?

A. Gravity B. Molecular Attraction C. Friction D. All are forces of resistance ✓✓✓✓✓✓

31. Which of the following is a force of resistance

C. Three

32. A lever is comprised of how many parts?

C. At the opposite end of the resistance

33. In the third class lever, the fulcrum is located

A. 746 watts

34. One horsepower is equal to

A. The same

40. A 50-kg sack is lifted 2 m in the same time as a 25-kg sack is lifted 4 m. The power expended in raising the 50-kg sack compared to the power used to lift the 25-kg sack is

B. False

41. A machine can save time or work

A. Dependent on the mass of the barbell

42. The power expanded when a barbell is raised 2.0 m in 2 s is

B. False

46. The effort arm of a lever is the part of the lever that resists the applied force.

A. gain force B. increase speed C. Increase distance D. Change direction E. ALL OF THE ABOVE✓✓✓✓✓✓

50. First class levers may

B. Twice the usual power output

6. If you do work on an object in half the time, your power output is

D. 1W

7. Exert 1N for a distance of 1m in 1s and you deliver a power of

A. Four times as much potential energy B. Twice as much potential energy C. Neither of these ✓✓✓✓✓✓

9. An object is raised above the ground gaining a certain amount of gravitational potential energy. If the same object is raised twice as high, it gains

B. Power

A job is done slowly, while an identical job is done quickly. Both jobs require the same amount of work, but different amounts of

B. While standing on the skateboard at the top of the hill

Igor carried a skateboard up a hill and then rode the skateboard down the hill. When Igor reached the bottom of the hill, he rolled to a stop. When did Noah have the most potential energy?

A. Coiled spring B. Fully charged batttery C. Water behind a dam D. Rock on top of a cliff E. All are correct ✓✓✓✓✓✓

Which of the following is an example of potential energy?

D. Resistance

29. The force that must be overcome in doing work?

A. Heat

15. When a car is braked to a stop, its kinetic energy is transferred to

C. 2nd

16. What class of lever is a wheelbarrow?

A. Gravity B. Molecular attraction C. Friction D. All of the above ✓✓✓✓✓✓ E. A&B

17. What is a type of resistance?

A. 5 ft/lbs B. 45 ft/lbs ✓✓✓✓✓✓ C. 90 ft/lbs D. None of the above

18. A man lifts a 15-pound box three feet, how much work is done?

B. Watt

27. Who was the originator of the concept of horse power?

B. 550 ft/lbs

28. One horsepower is equal to how much work per second?

D. Force and Distance

36. What must work contain?

A. The work input must theoretically equal the work output

37. The Law of Machines states that in ideal conditions

D. Energy may not be created or destroyed but it can be changed from one form to another

38. The Law of conservation of Energy states that

A. Both require the same amount of work

39. Which requires more work: lifting a 50-kg sack vertically 2 m or lifting a 25-kg sack vertically 4 m?

D. 40 J

43. A TV set is pushed a distance of 2m with a force of 20 N that is in the same direction as the set moves. How much work is done on the set?

A. 10 N

44. It takes 40 J to push a large box 4 m across a floor. Assuming the push is in the same direction as the move, what is the magnitude of the force on the box?

B. False

45. A watt is equal to the amount of work that is accompanied when a force of one Newton moves an object of a distance of one meter.

B. Lifting a bag of groceries

47. Which of the following is the best example of work being done on an object?

A. 50 W

48. Using 1000 J of work, a toy elevator is raised from the ground floor to the second floor in 20 s. How much power dies the elevator use?

B. False

49. You always get less out of a machine that you put in due to the force of gravity.