1. An engine pumps 2000kgs of water in 1 minute to an average height of 10m.Calculate the power of the engine if 30% of the energy is wasted in the process.

2. A water pump of power 1.5KW draws water through a mean height of 10m to fill a tank 4m x 3m x 4m. Calculate the time taken to fill the tank

1.Given:

mass of water, m = 2000 kg

time taken, t = 1 minute = 60s

height, h = 10m

work done to pump the water, W = mgh

Power required, P = mgh/t = 3266.6 W = 3.2 kW

Let the power of the engine be P'. 

⇒0.7 P' = P

⇒P' = 4.57kW 

Power of the engine is 4.57 kW. 

2.Given:

P = 1.5 KW = 1500 W

h = 10m

Volume of the tank, V = 4X3X4 m³ = 48m³

Mass of water, m = ρV = 1000 X 48 kg = 48000 kg

Time taken, t = work done/ Power = mgh/P

t = [48000*9.8*10]/ 1500 = 3136 s = 52.3 minutes