2.11.6 Power

Power is the rate at which work is done, which means how fast a work is done.

It is also a measure of how fast a form energy is converted to another form.

Formula:


Example:
An electric motor takes 20 s to lift a box of mass 20kg to a height of 1.5 m. Find the amount of work done by the machine and hence find the power of the electric motor.

Answer:
Work done,
W = mgh = (20)(10)(1.5) = 300J

Power,