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ch8 voc
| Question | Answer |
|---|---|
| work | The transfer of energy to an object by using a force that causes the object to move in the direction of the force. |
| joule | The unit used to express energy. |
| power | The rate at which energy is transfered. |
| watt | The unit used to express power. |
| machine | A device that makes work easier by changing the size or direction of a force. |
| work input | The work done on a machine. |
| work output | The work done by a machine. |
| mechanical advantage | A number that tells how many times a machine multiplies force. |
| mechanical efficiency | A comparison of a macheines's work output with the work input. |
| lever | A simple machine that consists of a bar that pivots at a fixed point called a fulcrum. |
| pully | A simple machine that consists of a wheel over which a rope chain or wire passes. |
| wheel and axle | A simple macheine consisting of two circular objects of different sizes. |
| inclined plain | A simple machine that is a straight, slanted surface. |
| wedge | A pair of inclined plains that move. |
| screw | A simple machine that consists of an inclined plain wrapped arouned a cylinder. |
| compound machine | A machine made of more than one simple machine. |