Question

from a waterfall , water is pouring down at rate of 100 kg per sec if the height is 100m the power delivered is

Answer 1

mass pouring = 100 kg/s
height = 100m

Maximum energy that can be delivered per second = mgh
⇒ Max. Power = 100kg/s × 9.8 m/s² × 100m
⇒ Max. Power = 98000 J/s
⇒ Max. Power = 98 kJ/s = 98 kW

But all the energy is not transferred from water. The water which fell still has some Kinetic energy. We normally take 50% efficiency. So 50% of maximum Power is delivered.

So power delivered = 98 × (50/100) = 49 kW

Answer 2

hello dear.....

Power = work done / time taken

or P = mgh / t

P = (m/t) gh = 100 x 10 x 100 = 100 kW

Thank you...