Question

a pump can take out 36000kg of water per hour from a 100m deep well .if the efficiency of the pump is 50% its powe

Answer 1

E = mgh

E = 36,000(10)(100) kgm^2/s^2 = 36,000 kJ (Since 1 kgm^2/s^2 = 1 J)

P = E/t = 36,000 kJ/(3,600s) = 10 kW ( Since 1 J/s = 1 W)

With 50% efficiency, P =10/0.5 = 20 kW

ANS = (D)

Answer 2

We get work by MGH

We=36000*100*10=36*10^6

As per question it can take out 36000kg per hour (means in 3600sec )

So we get power=work/time

36*10^6/3600 so we get 10k watt

Effiency=input power/output power

so 50/100=10^4/output power

so output power is equal to 20kw

option (D)

Mark as brilliant plz