A water pump produces 20m^3/h at a height of 80m.The pump is driven by a diesel engine that develops 7kW to produce the water.

Question

1.calculate work done per hour
2. Calculate power required to produce the water at a height of 80m
3. Calculate the efficiency of the pump

Answer 1

water weighs 997kg/m^3 * 9.81N/kg = 9780.57 N/m^3
work = force * distance = 9780.57N * 80m = 782445 N-m/hr

Now use power = 1W = 1N/s

and divide to find the efficiency