Question

An electric motor transforms 125 J of electrical energy into mechanical energy in 3 minutes. What is the power of the motor?

Answer 1

Given:

The electric motor transforms electrical energy,

$E=125\text{ J}$

time taken in this transformation is,

$\begin{gathered} t=3\text{ m} \\ =3\times60\text{ s} \\ =180\text{ s} \end{gathered}$

To find:

The power of the motor

Explanation:

Power is the rate of change in energy. So,

$\begin{gathered} P=\frac{E}{t} \\ =\frac{125}{180} \\ =0.69\text{ W} \end{gathered}$

Hence, the power is 0.69 W.