1. The problem statement, all variables and given/known data In a U-shaped tube, water is flowing with velocity v. The flowing rate is u, and it's constant. What force does the water exert on the wall of the tube. 2. Relevant equations F = dp/dt u = m/t 3. The attempt at a solution The change in momentum is [itex] mv - (-mv)[/itex] or [itex] 2uv \Delta t[/itex] so [itex] F = 2uv[/itex] is this correct?