1. The problem statement, all variables and given/known data This is my problem in all its glory. 2. Relevant equations f = uN 3. The attempt at a solution For part a I simply did that tan(alpha) = f/N and therefore alpha = arctan(f/N). This simplifies to alpha = arctan(u). I believe this part is correct. The second part of this question is what gets me. I set up the sum of the moments for the bar. My equation is: W*sin(alpha)*L/2 - N*sin(alpha)*L + f*cos(alpha)*L = 0 Algebra gave me that N = - W*sin(alpha) / [2*(u*cos(alpha) - sin(alpha)] I made a FBD for the plate and the equations I got were that F - f = 0 and Ngroundonplate - N = 0. (The plain N being the normal force of the bar on the plate) Since f = uN, substitution of N gave me f = - u*W*sin(alpha) / [2*(u*cos(alpha) - sin(alpha)] and then dividing top and bottom by cos(alpha) I got that f = INFINITY. If this makes sense, can anyone explain how? If it's wrong can anyone point me in the right direction?