Part a: We begin by drawing the free-body diagram of the block and writing the two force equilibrium equations.

Since the condition is impending slipping, the friction force is related to the normal force as

Substituting for F and solving the two equilibrium equations gives

Part b: the angle of static friction is the angle of the resultant force at the surface of contact, and is found as

Part c: To determine if tipping is a possibility, we solve for h_max and compare it to h= 60 in. Using the equilibrium of moments, we find

Since h_max>h, no tipping will occur.