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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 |