A water pump lifts water from a level 10 m below the ground. Water is pumped at a rate of 30 kg/minute with negligible velocity. Calculate the minimum horsepower the engine should have to do this.
Rate = 30 kg/minute = 0.5 kg per sec
We need to pump 0.5 kg of water to a height of 10m upwards in 1 sec.
Power=Work done/Time
= mass × acceleration due to gravity × height/ time
= 0.5 × 9.8 × 10
= 49 J/s or W
= 49/746 horsepower
= 0.066 hp
= 6.6×10-2 hp