Question

Define power.

Answer 1

Power is defined as the rate of doing work. It is equivalent to an amount of energy consumed per unit time.
$P=\frac{dW}{dt}$
We know that, $W=\overrightarrow{F}.\overrightarrow{ds}$
$\Rightarrow P=\frac{d(\overrightarrow{F}.\overrightarrow{ds})}{dt}$
When the force is constant,
$\Rightarrow P=\overrightarrow{F}.\frac{\overrightarrow{ds}}{dt}\Rightarrow P=\overrightarrow{F}.\overrightarrow{v}$
In the SI system, the unit of power is joule per second (J/s), also known as the watt (W).