Q411. The assembly consists of two slender rods each of weight 40 lb and length L = 4 ft and a disk of weight 16 lb and radius r = 1 ft. The stiffness of the spring is k = 5 lb/ft. The spring is unstretched when = 45 and the assembly is released from rest at this position. At the instant =0, 1) Show that C is the instantaneous center of zero velocity of the bar BC. 2) Determine the angular velocities of the disk, rods AB and BC. The disk rolls without slipping. Take IG = m for the uniform bar, Imr for the uniform disk and g = 32.2 ft/s. - Conservation of energy rigid body L B