1. The problem statement, all variables and given/known data . The sign shown below consists of two uniform legs attached by a frictionless hinge. The coefficient of friction between the ground and the legs is µ. Which of the following gives the maximum value of θ such that the sign will not collapse? (A) sin θ = 2µ (B) sin θ/2 = µ/2 (C) tan θ/2 = µ (D) tan θ = 2µ (E) tan θ/2 = 2µ Diagram here : http://www.aapt.org/physicsteam/2014/upload/exam1-2013-1-6-unlocked.pdf Page 2, Diagram 6 2. Relevant equations 3. The attempt at a solution I drew a FBD and got a force of gravity for each leg with force mg down (relative to the surface on the ground) , normal force of mgcos((180-theta)/2) up (relative to the surface of the leg), and friction of mu*N towards the interior of the sign. The question is where do I go from here?