A water pump operates with an efficiency of 75%. It is used to raise water from a well of depth 15 m and discharge it at ground level through a pipe at a speed of 12 m s-1. The pump delivers water at a constant rate of 20 kg s-1.
Taking g=9.8 m s−2g = 9.8\text{ m s}^{-2}g=9.8 m s−2, what is the minimum electrical power input required by the pump?
3.29 kW3.29\text{ kW}3.29 kW
3.92 kW3.92\text{ kW}3.92 kW
5.84 kW5.84\text{ kW}5.84 kW
4.38 kW4.38\text{ kW}4.38 kW