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Phys Sci - Chap 14
vocabulary words
| Question | Answer |
|---|---|
| work | product of the distance and the force in the direction an object moves |
| joule | SI unit of work (J), equal to 1 newton-meter |
| power | the rate of doing work |
| watt | Si unit of power (W), equal to one joule per second |
| horsepower | common unit of power, equal to about 746 watts |
| machine | device that changes a force |
| input force | force exerted on a machine |
| input distance | distance through which the input force acts in a machine |
| work input | work done on a machine as the input force acts through the input distance |
| output force | force exerted by a machine |
| output distance | distance an output force acts through in a machine |
| work output | work done by a machine as the output force acts through the output distance |
| mechanical advantage | number of times that a machine increases an input force |
| actual mechanical advantage | ratio of the output force to the input force in a machine |
| ideal mechanical advantage | mechanical advantage of a machine in the absence of friction |
| efficiency | percentage of the work input that becomes the work output in a machine |
| lever | a rigid bar that is free to move around a fixed point |
| fulcrum | fixed point a lever rotates around |
| input arm | distance between the fulcrum in a lever and the input force |
| output arm | distance between the fulcrum in a lever and the output force |
| wheel and axle | simple machine that consists of two rigidly attached disks or cylinders, each one with a different radius |
| inclined plane | slanted surface along which a force moves an object to a different elevation |
| wedge | V-shaped object whose sides are two inclined planes sloped toward each other |
| screw | inclined plane wrapped around a cylinder |
| pulley | simple machine that consists of a rope that fits into a groove in a wheel |
| compound machine | combination of two or more simple machines that operate together |