A disc of radius R is rolling without slipping on a fixed circular track of radius 2R. Line joining the centre of the disc and centre (O) of circular track is rotating with constant angular velocity in clockwise sense. A rod AB whose end A is attached to a small ring which can move only along a fixed horizontal rod and other end of rod B is pivoted at B, R/2 distance above centre of disc as shown. Find the angular velocity of rod AB at the instant when rod AB is making an angle 30 with horizontal and centre of the disc is directly above the centre (O) of the track as shown in figure.(Assume rod can rotate freely about hinge point B)
