A rod PQ of mass M and length L is hinged at end P. The rod is kept horizontal by a massless string tied to point Q as shown in figure. When string is cut, the initial angular acceleration of the rod is

A circular platform is mounted on a frictionless vertical axle. Its radius R = 2 m and its moment of inertia about the axle is 200 kg m². It is initially at rest. A 50 kg man stands on the edge of the platform and begins to walk along the edge at the speed of 1 ms^$$-$$1 relative to the ground. Time taken by the man to complete one revolution is

A car of mass m is moving on a level circular track of radius R. If $$\mu $$_s represents the static friction between the road and tyres of the car, the maximum speed of the car in circular motion is given by

The moment of inertia of a uniform circular disc is maximum about an axis perpendicular to the disc and passing through