Question

A pump is used to lift 500 kg of water from a depth of 80 m in 10 s.Calculate:

(a) the work done by the pump,

(b) the power at which the pump works, and

(c) the power rating of the pump if its efficiency is 40%.

Answer 1

Work done in raising a 500kg mass to a height of 80m against the force of gravity is:
(a) W = mg × h = mgh W = 500 × 10 × 80 = 4 × 100,000 J
(b)


(c)
efficiency 40%=0.4


power rating = useful power / efficiency
= 40/(40/100)
=100 kW