A pump is required to lift 1000 kg of water per minute from a well and eject it with a speed of 10 m/s. The horse power of the engine needed is..?

We are not given the depth of the well. Let it be ‘x’.

1000 kg of water is to be lifted per minute.

So, weight of water to be lifted is = 1000×9.8 = 9800 N

Work done in lifting this weight of water from depth ‘x’ is = 9800x J

Now the 1000 kg that is lifted is ejected with speed 10 m/s. So, work done in giving it the kinetic energy is = ½ × 1000 × 10² = 50000 J

So, total work done is = (9800x + 50000) J

This work is done in 1 minute or 60 s.

So, power of engine is = (9800x + 50000)/60 W

Thus, the power in hp is = (9800x + 50000)/(746×60) hp

= {(9800x + 50000)/44760} hp