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. |
Joule | the unit used to express energy; equal to the amt. of work done by a force of 1 N acting through a distance of 1 M in the direction of the force (symbol, J) |
Power | the rate at which work is done or energy is transformed |
Watt | the unit used to express power; equivalent to joules per second (symbol,W) |
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; the product of the input force and the output force and the distance through which the force is exerted |
Mechanical Advantage | a number that tells how many times a machine multiplies force. |
Mechanical Efficiency | a quantity, usually expressed as a percentage, that measures the ratio of work output to work input, it can be calculated by dividing work output by work input. |
Lever | a simple machine that consists of a bar that pivots at a fixed point called a "fulcrum". |
Pulley | machine that consists of a wheel over whcih a rope, chain, or wire passes |
Wheel and Axle | machine that consists of two circular objects of different sizes, the wheel is the largest of the other two circular objects |
Inclined Plane | machine that is a straight, slanted surface, which facilitates the raising of loads; ex. a ramp |
Wedge | a machine made up of two inclined planes and that moves; often used for cutting |
Screw | a machine that consists of an inclined plane wrapped around a cylinder |
Compound Machine | a machine made of more than one simple machine |
Work Output | the work done by a machine; the product of the output force and the distance through which the force is exerted |