1. The problem statement, all variables and given/known data If the coefficient of static friction at B is μs = 0.3, determine the largest angle θ, and the minimum coefficient of static friction at A, so that the roller remains self- locking, regardless of the magnitude of the force P applied to the belt. Neglect the weight of the roller and neglect friction between belt and vertical surface. 2. Relevant equations ƩM=0 ƩFx=0 ƩFy=0 FA=μANA FB=μBNB=0.3NB 3. The attempt at a solution I have attempted the solution quite a few times a couple of different ways. I keep getting stuck with variables that I can't solve for, so I have come to the conclusion that I am probably not going about it the right way. My first attempt, I took the moment about A, and then summed up the forces in the x and y directions, but wound up not being able to solve for θ or μA. I attached an attempt at a free body diagram, perhaps I don't have the friction forces going in the right direction? I would appreciate any help!