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Chapter 20
Question | Answer |
---|---|
work | the transfer of energy to an object by using a force that causes the object to move in the direction of the force W=F*d |
joule | unit of work |
power | the rate at which work is done or energy is transformed |
watt | power unit |
machine | a device that helps do work by either overcoming a force or changing the direction of the applied force |
work input | the work done on a machine |
work output | the work done by a machine |
mechanical advantage | a number that tells how many times a machine multiplies force MA= output force/input force |
mechanical efficiency | ratio of work output to work input ME= work output/work input |
lever | a simple machine that consists of a bar that pivots at a fixed point called a fulcrum |
pulley | a simple machine that consists of a wheel over a rope, chain, or wire passes |
wheel and axle | a simple machine consisting of two circular objects of different sizes; the wheel is the larger of the two circular objects |
inclined plane | a simple machine that is straight, slanted surface,which facilitates the raising loads; ramps |
wedge | a simple machine that is made up of two inclined planes and that moves; often used for cutting |
screw | a simple machine consists of an inclined plane that is wrapped around a cylinder |
compound machine | a machine made of more than one simple machine |