The power of a motor pump is 5 kW How much water per minute the pump can raise to a height of 20 m? (Take, g = 10 ${{ms}^{-2}}$)

Time, t = 60 s, height, h = 20 m

Energy supplied to the pump = Power X Time = 5 kW x 1 min = 5000W x 60s = 3 x ${{10}^{5}}$

Energy E = mgh

m =E/gh = 3 x ${{10}^{5}}$ / 10 x 20 = 1.5 x ${{10}^{3}}$

So, volume of water lifted in a minute = mass/density = 1.5 x ${{10}^{3}}$ / ${{10}^{3}}$ = 1.5 ${{m}^{3}}$