Physical Science Chapter 14 Test Review

1. Physical Science Chapter 14 Test Review

2. Warm-Up Oct. 2 • What do you have in this class tomorrow? • What is the unit for work? • Where is the fulcrum on a 1st class lever?

3. 1. The rate at which work is done is called __ a. force b. mechanical advantage c. power d. efficiency c. power

4. 2. In which of the following is no work done? a. climbing stairs b. pushing a shopping cart c. lifting a book d. none of the above d. None of the above

5. 3. A device that changes the size or direction of force used to do work is called a(n) machine

6. 4. What is the unit of work? a. joule b. watt c. newton/meter d. all of the above a. joule

7. True or False? 5. You calculate work by multiplying allthe forces acting on the object by the distance the object moves. true

8. 6. If you perform 40 joules of work lifting a 10 N box from the floor to a shelf, how high is the shelf? a. 0.3 m b. 4.0 m c. 20 m d. 400 m b. 4.0 m

9. 7.What is the MA of Machine B in Figure 14-3? a) 2 b) 3 c) 5 d) 1 e) 4 e. 4

10. 8. A machine is a device that can multiply a. force. b. work. c. power. d. all of the above a. Force

11. 9. If the ramp shown in Figure 14-2 was coated with a smoother surface, how would the ramp’s efficiency change? a) Its efficiency would increase, friction would decrease. b) Its efficiency would decrease, friction would increase. c) Its MA would increase, friction would decrease. d) Its MA would decrease, friction would increase. a. Its efficiency would increase, friction would decrease.

12. 10. How can a machine make work easier for you? a. by decreasing the amount of work you do b. by changing the direction of your force • by increasing the work done by the machine • none of the above b. By changing the direction of your force

13. 11. For work to be done on the object, the object has to a. be efficient b. have friction c. move d. have a force applied to it c. move

14. 12. How can you make the work output of a machine greater than the work input? a. by decreasing friction b. by increasing the input force c. by increasing the output distance d. none of the above d. None of the above

15. 13. How will a lubricant affect the efficiency of a simple machine such as a pulley? a. A lubricant will have no affect on a simple machine’s efficiency b. A lubricant will decrease a simple machine’s efficiency by increasing friction c. A lubricant will increase a simple machine’s efficiency by decreasing friction. d. A lubricant will decrease a simple machine’s efficiency by decreasing friction c. A lubricant will increase a simple machine’s efficiency by decreasing friction.

16. 14. The actual mechanical advantage of a machine a. cannot be less than 1. • decreases as the input distance increases. • increases with greater friction. d. is less than the ideal mechanical advantage of the machine. d. Is less than the ideal mechanical advantage of the machine.

17. 15. Which of the following statements is true? a. To increase power, you can decrease the amount of work you do in a given amount of time, or you can do a given amount of work in more time. b. To increase power, you can increase the amount of work you do in a given amount of time, or you can do a given amount of work in less time. c. To increase power, you can decrease the amount of work you do in a given amount of time, or you can do a given amount of work in less time. d. To increase power, you can increase the amount of work you do in a given amount of time, or you can do a given amount of work in more time. b. To increase power, you can increase the amount of work you do in a given amount of time, or you can do a given amount of work in less time.

18. 16. A 120m long ski lift carries skiers from a station at the foot of a slope to a second station 40 m above. What is the IMA of the lift? a. 0.3 b. 40 c. 3 d. 160 c. 3

19. 17. Using Figure 14-4, If you pushed down on the lever and the lever lifted a box 4 m, how much work did the lever do? a. 920 J b. 920 c. 57.5 J d. 920 W e. 57.5 a. 920 J

20. 18. An ax is an example of a(an) a. inclined plane. b. wedge. c. lever. d. wheel and axle. b. wedge

21. 19. An inclined plane reduces the effort force by a. increasing the work. b. reducing the effort distance. c. increasing the distance through which the force is applied. d. reducing the work. c. Increasing the distance through which the force is applied.

22. 20. Which of the following is an example of a wheel and axle? a. hammer b. an automobile steering wheel c. a jar lid d. a pencil b. An automobile steering wheel

23. 21. If you grease a ramp to make a box slide more easily, what happens to the ramp’s mechanical advantage? a. it decreases b. it is multiplied by 100 c. it stays the same d. it increases c. It stays the same

24. 22. An example of a compound machine is a a. crowbar. b. ramp. c. bicycle. d. seesaw. c. bicycle

25. 23. If you exert a force of 850 N to walk 5.5 m up a flight of stairs in 25 s, how much power do you use? a. 187 W b. 3863.64W c. 18.7 W d. 116,875 W e. 6.18 W a. 187 W

26. 24. For work to be done on the object, the object has to ____________________. Move in the direction of the force