Question

Water flows through a horizontal pipe of varying area of cross section at the rate 15 cubic metre per minute. Find the radius of pipe when water velocity is 3 $m{s}^{-1}$.

Answer 1

Given,

$v=3m/s$

$R=15m^3/min$

The volume of water per second,

$R=\frac{15}{60}=0.25m^3/s$

We know that, $R=Av$

$A=\frac{R}{v}=\frac{0.25}{3}=\frac{1}{12}{m}^2$

Area , $\pi r^2=\frac{1}{12}$

$r^2=\frac{1}{12\pi }$

$r=\sqrt{\frac{1}{12\times 3.14}}=0.1629m$

$r=16.29cm$