1. Work and Machines

2. Work is being done when you exert a force that moves an object in the direction of the force.

3. The unit for work is the Joule.

4. Power is how fast work is being done.

5. A ___ is a device that helps make work easier by changing the size or direction of a force. machine

6. Examples of machines include a pair of scissors, a screw, a bottle opener.

7. The work you do on a machine is called work input.

8. The work done by the machine is the work output.

9. A ___ is a simple machine consisting of a bar that pivots at a fixed point, called a fulcrum. lever

10. An ___ is a simple machine that is a straight, slanted surface. inclined plane

11. A ramp is an example of an inclined plane.

12. A ___ is a double inclined plane that moves. wedge

13. A zipper is made from three wedges.

14. A ___ is an inclined plane that is wrapped in a spiral. screw

15. A jar lid is an example of a screw.

16. A ___ is a simple machine consisting of two circular objects of different sizes. wheel and axle

17. A doorknob, wrench and Ferris wheel are examples of a wheel and axle.

18. A ___ is a simple machine consisting of a grooved wheel that holds a rope on a cable. pulley