An electric winch is used to lift a heavy crate. The useful work done against gravity in lifting the crate is 4800 J.
The efficiency of the winch system is 75%.
Calculate the total work done by the electric motor.
Use the equation:
efficiency=useful work donetotal work done by the motor×100% \text{efficiency} = \frac{\text{useful work done}}{\text{total work done by the motor}} \times 100\% efficiency=total work done by the motoruseful work done×100%