2. Work  The product of the force and distance when a force is used to move an object

3. Joule  A unit of work equal to one Newton- meter

4. Machine  A device that changes the amount of force exerted; the distance over which force is exerted, or the direction in which force is exerted.

5. Input force  The force exerted on a machine

6. Output force  The force exerted on an object by a machine

7. Mechanical advantage  The number of times the force exerted on a machine is multiplied by the machine

8. Efficiency  The percentage of the input work that is converted to output work

9. Actual mechanical advantage  The mechanical advantage that a machine provides in a real situation

10. Ideal mechanical advantage  The mechanical advantage that a machine would have without friction

11. Inclined plane  A simple machine consisting of a flat surface with one end higher than the other

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

13. Screw  A simple machine consisting of an inclined plane wrapped around a central cylinder to form a spiral

14. Lever  A simple machine consisting of a rigid object that pivots about a fixed point

15. Fulcrum  The fixed point around which a lever pivots

16. Wheel and axle  A simple machine consisting of two circular or cylindrical objects that are fastened

17. Pulley  A simple machine consisting of a grooved wheel around which is wrapped around a rope, cable, or chain

18. Compound machine  A device that combines two or more simple machines