A ring of mass `m` and radius `r` rotates about an axis passing through its centre and perpendicular to its plane with angular velocity `omega`. Its kinetic energy is

A disc of mass 2 kg and radius 0.2 m is rotating about an axis passing through its centre and perpendicular to its plane with an angular velocity 50 rad/s . Another disc of mass 4 kg and radius 0.1m rotates about an axis passing through its centre and perpendicular to its plane with angular velocity 100 rad/s. If the two disc are coaxially coupled, then the angular velocity of coupled system would be

A thin uniform circular disc of mass M and radius R is rotating in a horizontal plane about an axis passing through its centre and perpendicular to the plane with angular velocity omega . Another disc of same mass but half the radius is gently placed over it coaxially. The angular speed ofthe composite disc will be:

A thin uniform circular disc of mass M and radius R is rotating in a horizontal plane about an axis passing through its centre and perpendicular to its plane with an angular velocity omega . Another disc of same dimensions but of mass (1)/(4) M is placed gently on the first disc co-axially. The angular velocity of the system is

An annular circular brass disk of inner radius 'r' and outer radius 'R' is rotating about an axis passing through its centre and perpendicular to its plane with a uniform angular velocity 'omega' in a uniform magnetic filed of induction 'B' normal to the plane of the disk. The induced emf between the inner and outer edge of the annular disk is

The moment of inertia of a copper disc, rotating about an axis passing through its centre and perpendicular to its plane

Charge Q is uniformly distributed over a nonconducting ring of radius R and mass m. It is made to rotate about an axis passing through its centre and perpendicular to its plone with an angular velocity of rotation omega . Find its magnetic dipole moment and its ratio with angular momentum.