## August 14, 2011

### 4.4 Efficiency

Recall and use the relationship:

$efficiency = \frac{useful\: energy\: output}{total\: energy\: input}$

Remember: Efficiency is generally measured as a Percentage (%) so in order to get the answer as a percentage you may need to multiply the answer by 100, otherwise you will result with a number between 1 and 0. And  energy, as usual, is measured Joules (J)