Water flows out of a big tank along a tube bent at right angles, the inside of the tube is of radius `r`. The length of the horizontal portion is `l`. The rate of water flow is `Q`. Find the moment of reaction forces of flowing water, acting on the tube walls relative to point `O`.

Explanation

Velocity of flow `=v=Q/(pir^(2))`
Reaction force `F=rhoAv^(2)`
`impliesF=rhopir^(2)(Q/(pir^(2)))^(2)=(Q^(2))/(pir^(2))rho`
Torque about `O+Fl=(Q^(2)rhol)/(pir^(2))`