Question

An engine pumps 800 kg of water through height of 5 m in 40 seconds, the power of engine if its efficiency is 40% (g = 10m/s sq.)

Answer 1

Hey.

Here is the answer.

Total Potential Energy = m g h = 800×10×5

= 40000 J

Power = PE / time = 40000/40 = 1000 W

As efficiency is 40% , so let original Power = p

So, 40 % of p = 1000 W

so, 0.40p = 1000

so, p = 1000/0.40 = 2500 W

So, original Power is 2500 W.

Thanks.