The ends of the 20-lb uniform rod AB are attached to collars of negligible mass that slide without friction along fixed rods. A vertical force P is applied to collar B when u 5 25°, causing the collar...

The ends of the 20-lb uniform rod AB are attached to collars of negligible mass that slide without friction along fixed rods. A vertical force P is applied to collar B when u 5 25°, causing the collar to start from rest with an upward acceleration of 40 ft/s2 . Determine (a) the force P, (b) the reaction at A.