A uniform circular disc of mass ‘m’ and radius ‘a’ can rotate in a vertical plane about a horizontal axis through a point O on its circumference. The disc is held with the diameter OA through O horizontal and then released. If a constant frictional couple of 'mga/2pie' opposes the motion, the angular speed when OA is vertical will be
A uniform circular disc of mass ‘m’ and radius ‘a’ can rotate in a vertical plane about a horizontal axis through a point O on its circumference. The disc is held with the diameter OA through O horizontal and then released. If a constant frictional couple of 'mga/2pie' opposes the motion, the angular speed when OA is vertical will be