Find the useful power used in pumping 3425`m^(3)` of water per hour from a well 8 m deep to the surface , supposing 40 % of the horse power during pumping is wasted . What is the horse power of the engine ?

Explanation

Mass of water pumped , `m=3425m^(3)`
`=3425xx10^(3)kg`
Mass of `1m^(3)` water = 1000 kg
Depth of well d = 8 m ., Power wasted = 40 %
`therefore"efficiency",eta=60%`
time , t = 1 hour = 3600 sec.
Useful power `=("Actual work done")/("time "xx" efficiency")=("mgd")/(t.eta)`
Useful power `(3425xx10xx9.8xx8xx100)/(3600xx60)`
= 124315 watt , But 1 H.P = 746 W
`therefore` Useful power in H.P
`" "=(124315)/(746)=166.6H.P`