Motion of the 600-mm slender bar of mass 4 kg is controlled by the constrained movement...

Motion of the 600-mm slender bar of mass 4 kg is controlled by the constrained movement of its small rollers A and B of negligible mass and friction. The bar starts from rest in the horizontal position with θ = 0 and moves in the vertical plane under the action of the constant force P = 50 N applied normal to the bar at end C. Calculate the velocity v with which roller A strikes the wall of the vertical guide at θ = 90°.