In Prob. 8.30, determine the range of values of the magnitude P of the vertical force applied at E for which the plate will move downward.
Prob. 8.30 The 50-lb plate ABCD is attached at A and D to collars that can slide on the vertical rod. Knowing that the coefficient of static friction is 0.40 between both collars and the rod, determine whether the plate is in equilibrium in the position shown when the magnitude of the vertical force applied at E is (a) P = 0, (b) P = 20 lb.
