What is power?
Physics · Middle School · Thu Feb 04 2021
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Power in physics is defined as the rate at which work is done or energy is transferred. It is a measure of how quickly work can be done. The unit of power in the International System of Units (SI) is the watt (W), which is equal to one joule per second (J/s).
Mathematically, power (P) is expressed as:
\[ P = \frac{Work}{Time} \]
where "Work" is the amount of energy transferred or converted and "Time" is the period over which the work is done.
If we consider force (F) and displacement (s), and assume that the force is applied in the direction of the displacement, then Work (W) is defined as:
\[ W = F \times s \]
Thus, by combining these two equations, power can also be expressed in terms of force and velocity (v), because velocity (v) is displacement (s) divided by time (t):
\[ P = \frac{F \times s}{t} = F \times v \]
This shows that power is also the product of force and the velocity at which that force is applied.