| A | B |
|---|
| work | when a force causes an object to move in the direction of the force |
| power | the rate at which work is done |
| watt (W) | rate used to express power (also joules/second) |
| joule | SI unit for work (Newton X meter) |
| F X D | formula for work |
| W/t | formula for power |
| machine | a device that helps make work easier by changing the size or direction of the force |
| work input | the work you do on a machine |
| work output | the work done by the machine |
| mechanical advantage | tells you how many times the machine multiplies force |
| output force/input force | formula for mechanical advantage |
| mechanical efficiency | a comparison of a machine's work output with the work input |
| work output/work input X 100 | formula for mechanical efficiency |
| lever | a simple machine consisting of a bar that pivots at a fixed point and are used to apply force to a load |
| fulcrum | the fixed point in a lever |
| inclined plane | a simple machine that is a straight, slanted surface |
| wedge | a double inclined plane that moves |
| screw | an inclined plane that is wrapped in a spiral |
| wheel and axle | a simple machine consisting of two circular objects of different sizes |
| pulley | a simple machine consisting of a grooved wheel that holds a rope or a cable |
| fixed pulley | a pulley that does not increase force and is attached to something that does not move |
| movable pulley | a pulley that is attached to the object being moved and it increases force on the object |
| compound machine | a machine that is made of two or more simple machines |
