My question is a little different in that I don't need help with the calculations for my problem, but rather I just need help understanding a concept. Take a look at the situation below: [PLAIN]http://img546.imageshack.us/img546/3459/phys.png [Broken] The problem is then, "What is the maximum force F that can be applied if the block is not to slide on the bracket?" I tried doing the problem and ended up getting the wrong answer. Upon asking my professor what I did wrong, I was told that the force acting on the bracket in the +x direction (to the right) is [itex]2\vec F[/itex]. I've tried and tried to understand this, and maybe I'm just stupid, but I simply don't get it. No matter how I think about it, it seems to me that the force acting on the bracket should be [itex]\vec F[/itex], not [itex]2\vec F[/itex]. Could anyone try to explain this to me? I really appreciate your help. Thanks.