1. The problem statement, all variables and given/known data Calculate the force F1 to bend the beam AB to a radius of 7.5m. Assume the beam is a steel tube 200mm OD with wall thickness 20mm. The arm's AC and BD can be assumed rigid. The force F1 acts on pivots at C and D and is always in the x direction. 2. Relevant equations I = pi (do4 - di4) / 64 3. The attempt at a solution My first thought was to assume the beam was fixed at one end and then work out the deflection required to achieve a a radius of 7.5m. From this I substituted into the deflection formula to work out a point load need on the end of the cantilevered beam to produce the deflection. I think i should be calculating the moment at point C and D but I'm struggling a bit, any help would be greatly appreciated.