| A | B |
|---|
| work | occurs when a force cause an object to movie in the direction of the force FxD |
| joule | unit of measure for work |
| power | the rate at which work is done W/T |
| watt | unit of measure for power |
| machine | a device that helps make work easier by changing the size or direction of a force |
| work input | the work you do on a machine |
| work output | the work done by the machine |
| mechanical advantage | tell you how many times the machine multiplies force output/input |
| mechanical efficiency | a comparison or a machine's work output with the work input output/input x100 |
| lever | simple machine consisting of a bar that pivots at a fixed point, called a fulcrum |
| 1st class lever | fulcrum is in the middle of the input(effort) and the load(resistince) MA=length of effort/length of resistence ex. seesaw |
| 2nd class lever | load(resistence) is between the input(effort) and the fulcrum ex.wheelbarrow |
| 3rd class lever | input(effort) is in the middle of the load(resistence) and the fulcrum ex. hammer |
| inclined plane | simple machine that is a straight , slanted surface. ex. ramp MA=length/height |
| wedge | double inclined plane the moves ex.knife MA=length/width |
| screw | an inclined plane that is wrapped in a spiral ex. cap closer the threads on a screw, greater the MA |
| wheel and axle | simple machine consisting of two circular objects of different sizes ex. doorknob MA=radius of wheel/radius of axle |
| pulley | simple machine consisting of a grooved wheel that holds a rope or cable kinds: fixed, movable, and block and tackle |
| compound machine | machine that has 2 or more simple machines ex. scissors |
