2. Chapter Twelve

3. the fixed point around which a lever pivots

5. a simple machine consisting of a grooved wheel around which is wrapped a rope, chain, or cable

7. a simple machine consisting of a rigid object that pivots about a fixed point

9. the mechanical advantage that a machine provides in a real situation

11. the product of force and distance when a force is used to move an object

13. two or more wheels linked together by interlocking teeth

15. a simple machine that consists of an inclined plane wrapped around a central cylinder to form a spiral

17. a unit of work equal to one newton-meter

19. a device that combines two or more simple machines

21. a simple machine consisting of two circular or cylindrical objects that are fastened together and rotate around a common axis

23. the mechanical advantage that a machine would have without friction

25. the force exerted on an object by a machine

27. a simple machine consisting of a device that is thick at one end and tapers to a thin edge at the other.

29. a device that changes the amount of force exerted or the direction in which the force is exerted

31. a simple machine consisting of a flat surface with one end higher than the other

33. the percentage of the input work that is converted to work output

35. The number of times the force exerted on a machine is multiplied by the machine

37. the force exerted on a machine

39. a band of connective tissue that attaches a muscle to a bone