Water flows out of a big tank along a big tube bent at right angles, the inner radius of tube is r. The length of horizontal section of the tube is equal to 'L'. The water flow rate is Q lit

Question

Water flows out of a big tank along a big tube bent at right angles, the inner radius of tube is r. The length of horizontal section of the tube is equal to 'L'. The water flow rate is Q litres/sec. Moment of reaction forces due to water flow acting on tube's wall, w.r.t. point O. Where $ρ$ is the density of water

Question figure

TestHub · Accepted Answer

Continuity gives the outlet speed: v = π r 2 Q ​ The upward reaction force is the outgoing momentum per second: F = ρQ v F = π r 2 ρ Q 2 ​ Its moment about the pivot O is anticlockwise: τ O ​ = F L τ O ​ = π r 2 ρ Q 2 L ​ This is option B in the printed convention. Use consistent volume units when substituting Q: 1 litre = 10^-3 cubic metre.

Physics - Fluid Question with Solution | TestHub

Options:

Doubts & Discussion