Power (physics)

In physics, power (symbol: P) is how fast work is done or energy is given from one thing to another. In the SI system of measurement, power is measured in watts (symbol: W).

It may take a certain amount of work to make a change in the world, such as lifting a heavy weight to a higher level. It makes no difference if the weight is lifted slowly or quickly. The same amount of work will have been performed. The difference between a slow lift and a quick lift is that a quick lift requires more power. This means the work can be done in a shorter time if there is more power available.

As a rate of change of work done or the energy of a subsystem, power is:

${\displaystyle P={\frac {W}{t}}}$

where

P is power,

W is work, and

t is time.

Power is also equal to force times velocity (or speed).