A body of mass 1 kg is suspended by a weightless string which passes over a frictionless pulley of mass 2 kg as shown in the figure. The mass is released from a height of 1.6 m from the ground. With what velocity does it strike the ground?

The moment of inertia of a rigid body about an axis

Seven identical discs are arranged in a planar pattern, so as to touch each other as shown in the figure. Each disc has mass $$m$$ radius $$R$$. What is the moment of inertia of system of six discs about an axis passing through the centre of central disc and normal to plane of all discs?

The angular speed of a motor wheel is increased from $$1200 \mathrm{~rpm}$$ to $$3120 \mathrm{~rpm}$$ in $$16 \mathrm{~s}$$. The angular acceleration of the motor wheel is