Question

An electric motor is used to do the 2.30 x104 J of work needed to lift an engine out of a car. If the motor draws a current of 3.2 A for 30 s, calculate the potential difference across the motor.

Answer 1

Given data

*The given energy is U = 2.30 x 10^4 J

*The given current is I = 3.2 A

*The given time is t = 30 s

The formula for the charge is given as

`q=It`

Substitute the known values in the above expression as

`\begin{gathered} q=(3.2)(30) \\ =96\text{ C} \end{gathered}`

The formula for the potential difference across the motor is given as

`U=qV`

Substitute the known values in the above expression as

`\begin{gathered} 2.30*10^4=(96)V \\ V=239.58\text{ V} \\ \approx240\text{ V} \end{gathered}`

Hence, the potential difference across the motor is V = 240 V