Here's a pulley problem that has got me stopped; I'd appreciate any help that's offered. There are two blocks, A (44 N) and B (22 N) connected via a rope that stretches over a pulley. Block A is resting on a table, and block B is hanging over the edge. Block C is positioned on top of Block A. The question reads: "Given that the coefficient of static friction between Block A and the tabel is 0.20, what is the minimum weight of Block C to keep Block A from sliding off the table?" (The answer that is given is 66 N, but I can't seem to get this) I tried starting off with: Block A=M=44N Block B=m=22N (let F stand for the friction force) T-F=Ma and mg-T=ma Solving for Tension and setting them equal gives: mg-ma=F+Ma Rearranging some more and solving for a gives: a= (mg-F)/(m + M) The Tension on Block A then becomes M(mg-F)/(m + M) = 8.8 N So then in order for Block A to resist motion, the Friction between it and the table must be equal to T, so F=T=8.8 .20 * (4.489 + C) * 9.8 = 8.8 but then the mass of C ends up being zero. Where did I go wrong?