| A | B |
|---|
| work | the product of distance and the force in the direction an object moves |
| joule | the SI unit of work, equal to 1 newton-meter |
| power | the rate of doing work |
| watt | the Si unit of power,equal to one joule per second |
| horsepower | a common unit of power, equal to about 746 watts |
| machine | a device that changes a force |
| input distance | the distance through which the input force acts in a machine |
| output force | the distance an output force acts through in a machine |
| workoutput | the work done by a machine as the output force acts through the output distance |
| input force | the force exerted on a machine |
| work input | the work done ona machine as the input force acts through the input distance |
| output distance | the distance an output force acts through a machine |
| mechanical advantage | the number of times that a machine increases an input force |
| actual mechanical advantage | the ratio of the output firce to the input force in a machine |
| ideal mechanical advantage | the mechanical advantage in the absence of friction |
| efficiency | the percentage of the work input that becomes work output in a machine |
| 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 adn the input force |
| output arm | the distance bewteen the fulcrum in alever and the output force |
| wheel and axle | a simple machine that consists of two rigidly attached disks or cylinders, each one with a diferent radius |
| inclined plane | a slanted surface along with a force moves an object to a different elevation |
| wedge | a V-shaped object whose sides are two inclined planes sloped toward each other |
| 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 two or more simpler substances that operate together |
