1. The problem statement, all variables and given/known data A horizontal tube of uniform cross sectional area 'A' is bent in the form of U. If the liquid of density 'ρ' enters and leaves the tube with velocity 'v' then how much external force is required to hold the bend stationary ? 2. Relevant equations 3. The attempt at a solution I think the bend in the tube provides centripetal force to the fluid flowing through it .As a result the fluid also exerts force on the bend. But then radius of the curve is not given. In 1 sec liquid of mass ρAv is flowing through any cross section of the tube. I would be grateful if somebody could help me with the problem.