"The figure below shows a uniform rod of length 4L and weight 20 N that is hinged freely at end A to a vertical wall. The rod is kept in equilibrium by a light inextensible string attached t a point at a distance L, from A and a weight of 50 N suspended at end B. 

Find

(a) The tension of the string.

(b) The force exerted by the wall on point A.

String 30 A 3L 50 N