Definition:SI/Power/Watt

Definition
The watt is the SI unit of power.

It is defined as being the rate at which $1$ joule of energy is uniformly transformed in $1$ second:


 * $1 \ \mathrm W = 1 \ \mathrm J \ \mathrm s^{-1}$

where:
 * $\mathrm J$ denotes the joule
 * $\mathrm s$ denotes the second.

Hence it can be understood as:
 * the rate at which work is done when the velocity of a body is held constant at $1$ metre per second against a constant opposing force of $1$ newton
 * the rate at which work is performed when an electric current of $1$ ampere flows across an electrical potential difference of $1$ volt.