| A | B |
|---|
| Work | the product of distance and force in the direction the object moves |
| Joule | SI unit of work |
| Power | the rate of doing work |
| Watt | SI unit of power |
| Horsepower | a common unit of power; equal to about 746 watts |
| Machine | a device that changes a force to make work easier |
| Input force | the force exerted on a machine |
| Input distance | the distance through which an input force acts |
| Work input | the work done on a machine |
| Output force | the force exerted by a machine |
| Output distance | the distance an output force acts |
| Work output | the work done by a machine |
| Mechanical advantage | the number of times that a machine increases an input force |
| Ideal mechanical advantage | the mechanical advantage of a machine in the absence of friction |
| Actual mechanical advantage | the ration of output force to the input force in a machine |
| Efficiency | the % of work input that becomes work output |
| Lever | a rigid bar that is free to move around a fixed point |
| Fulcrum | the fixed point a lever rotates around |
| Input arm | the distance between the fulcrum in a lever and the input force |
| Output arm | the distance between the fulcrum in a lever and the output force |
| Wheel and axle | a simple machine that consists of 2 rigidly attached disks or cylinders |
| Inclined plane | a slanted surface along which a force moves an object to a different elevation |
| Wedge | a v-shaped object whose sides are two inclined planes |
| Screw | an inclined plane wrapped around a cylinder |
| Pulley | a simple machine that consists of a rope that fits into a groove in a wheel |
| Compound machine | a combination of 2 or more simple machines that operate together |
