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zorro
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Homework Statement
A motor of power P is used to deliver water at a certain rate through a given horizontal pipe. To increase the rate of flow of water through the same pipe n times, the power of the motor is increased to P1. The ratio of P1 to P is?
The Attempt at a Solution
Let the velocity of flow of the water be 'v'.
The power required by the motor P = ρAv2*v, where A is the area of cross section of the pipe. Rate of flow of water, R = Av
P=ρRv2=ρR3/A2
It can be seen that P1=n3P.
The answer given is n:1
What's wrong?