Question

It is proposed to use a small waterfall to turn an electricity generator. 10 meter cube of water fall 50 meter per minute. Only one fifth of its energy can be obtained usefully. Show that the water can develop 16.7KW

Answer 1

Answer:

Explanation:

This question is kinda related to density. So we know the density of water is 1000kg/m3. And we are given the volume 10m3. So now we shall find the mass. Its 10000 kg. How? We know that density equals mass over volume so rearranging this formula we get mass equals density multiplied by volume. So 1000kg/ m3 times 10m3 which is 10000kg. Now after we have found the mass its easy to answer your question. We know that work against gravity is mgh. So 10000 kg*10 m/s2*50m is 5000000J. But only one fifth is used so divide the work done by five. So the used energy is 1000000. He have the work used and time so lets solve for power. Power=work done /time. 1000000/60sec. Power =16666.67 or 16.7kW