A drum of radius R and mass M, rolls down without slipping along an inclined plane of angle $$\theta $$. The frictional force

A round disc of moment of inertia $$I$$₂ about its axis perpendicular to its plane and passing through its centre is placed over another disc of moment of inertia $$I$$₁ rotating with an angular velocity $$\omega $$ about the same axis. The final angular velocity of the combination of discs is

Three particles, each of mass m gram, are situated at the vertices of an equilateral triangle ABC of side $$l$$ cm (as shown in the figure). The moment of inertia of the system about a line AX perpendicular to AB and in the plane of ABC, in gram-cm² units will be

A wheel having moment of inertia 2 kg m² about its vertical axis, rotates at the rate of 60 rpm about this axis. The torque which can stop the wheel's rotation in one minute would be