An industrial drainage pump is used to lift wastewater from a deep holding tank. The useful work done against gravity in raising the wastewater is 14.7 MJ14.7\text{ MJ}14.7 MJ.
The overall efficiency of the pump system is 42%.
Calculate the total work done by the pump's electric motor to complete this operation.
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%