Efficiency

= = =Efficiency by: Marty and Frank=
 * DEFINITION**:Efficency is the ratio of a machines output work to input work.


 * FACTS**:
 * All or most of work input becomes work output.
 * The more input that transformes to output the more efficient a machine has.
 * In real machines work output is alwys less than work input.
 * Efficiency is usually measured in percentage.
 * Efficiency is usually lowered by friction.


 * FORMULA**: %=wo/wi X 100

> > > **SORCES**: ipc textbook / []
 * Example Proplems**:
 * 1) Someone does 200J of work to raise a block with a pulley. The amount of work that the pulley does is 175J. What is the efficiency of the pulley? **87.5%**
 * 2) The efficiency of a lever is 65%. If the lever must do 250J of work to move a rock, how much work you must put into the lever? **384J**