Question

Water flows out of a big tank along with a horizontal tube $AB$ of length $l$ and radius $r$ and bent at right angles at the other end as shown in the figure. The rate of flow is $Q{m}^3/s$. Calculate the moment of the force exerted by the water on the tube about the end $A$.

Answer 1

We know that,

$Q=AV$

But $A=\pi r^2$

So,$V=Q/\pi r^2$

$Force=pA{V}^2$ ,$p=densityofwater$

$vForce=p\left(AV\right)V$

We know $AV=Q$ and $V=Q/\pi r^2$

So,$Force=p\times Q\times Q/\pi r^2$

Since , length is not negligible here,

$Force=p{Q}^{2}l/\pi r^2$