| A | B |
|---|
| work | occurs when a force causes an object to move in the direction of the force. |
| power | the rate at which work is done. |
| efficiency | the work a machine does compared to the energy needed to run the machine |
| horsepower | a unti for measuring the power of engines and motors. |
| 550 foot-pounds per second | 1 horsepower |
| watt | the unit used to express power |
| machine | a device that helps make work easier by changing the size or direction of a force |
| mechanical advantage | tells you how many times the machine multiplies force |
| mechanical efficiency | a comparison of a machine's work output with the work input |
| simple machines | the six machines from which all other machines are constructed |
| lever | a smiple machine consisting of a bar that pivots at a fixed point ( called the fulcrum) |
| inclined plane | a simple machne that is a straight, slanted surface |
| screw | an incline plane that is wrapped in a spiral |
| wedge | a double inclined plane that moves |
| wheel and axle | a simple machine consisting of 2 circular objects of different sized |
| pulley | a simple machine consisting of a grooved wheel that hold a rope or cable |
| compound machines | machines that are made of two or more simple machnes. |
