For electrical power and other forms of power, see Energy.

## Definition

In a physics term, power is the rate at which work takes place or energy is transmitted. It can also be defined as the amount of energy needed or used to complete an activity over a period of time.

## Units

The SI unit for power is the the Watt or "W". Other non SI units include:

• horsepower "HP",
• calories per hour, "cal/hr", and
• foot pounds per minute "ft-lb/min".

## Equation

The equation for power is ${\displaystyle P=W/t}$ where P is power, W is work and t is time. A second equation for power is ${\displaystyle P=E/t}$ where E is energy and t is time.