NOTE: You must draw a proper FBD for every problem and clearly indicate all forces and couples that are present for the problem.

Problem $1$:

Two bars, $AB$ and $BD,$ are pinned together at $B$ such that the angle between them is $.$ Bar $AB$ is pinned at A and has a length of $L.$ Bar $BD$ is pinned to a box at $D.$ Neglect the weight of the bars. The box has weight $W$ and rests on a rough surface with a coefficient of static friction of ${}_s.$ A horizontal force $P($to the right$)$ is applied at point $C,$ the midpoint of bar $AB.$ Do the following:

a$)$ Determine the value of $P$ to initiate slip.

b$)$ Using your answer from a $),$ is there a range of angle $$ such that a positive $P$ to the right can not cause the block to slip?