Rods AB and BC have weights of 15 lb and 30 lb, respectively. Collar C, which slides fre...

Rods AB and BC have weights of 15 lb and 30 lb, respectively. Collar C, which slides freely along the smooth vertical guide, has a weight of 5 lb. If the system is released from rest when θ = 0°, determine the angular velocity of the rods when θ = 90°. The attached spring is unstretched when θ = 0°.