1. The problem statement, all variables and given/known data A uniform bar with lenght c can slide a cylindrical surface with a radius of r. Determine the maximum angle theta that guarantees the equilibrium of the bar if the friction coefficient at the points of contact is u. 2. Relevant equations Friction force = u*N (where N is the normal force, and u is the friction coefficient). 3. The attempt at a solution Okay, I'm really lost with this exercise. I didn't understand the statement. The bar is at the top of a cylindrical surface, and can slide within it, or is the cylinder hollow and the bar is supported on both ends by the friction force (touching the inside walls of the cylinder)? For me, the second option makes more sense, but how would the bar slide then? I would appreciate any help.