A ring of radius `R` is first rotated with an angular velocity `omega` and then carefully placed on a rough horizontal surface. The coefficient of friction between the surface and the ring is `mu`. Time after which its angular speed is reduced to half is

A uniform circular ring of radius R is first rotated about its horizontal axis with an angular velocity omega_0 and then carefully placed on a rough horizontal surface as shown. The coefficient of friction between the surface and the rings mu . Time after which its angular speed is reduced to 0.5 omega_0 is

A ring of radius R is rotating with an angular speed omega_0 about a horizontal axis. It is placed on a rough horizontal table. The coefficient of kinetic friction is mu_k . The time after it starts rolling is.

A ring of radius R is rotating with an angular speed omega_0 about a horizontal axis. It is placed on a rough horizontal table. The coefficient of kinetic friction is mu_k . The time after it starts rolling is.

A ring of radius 'r' and mass per unit length 'm' rotates with an angular velocity omega in free space then:

A ring of radius 'r' and mass per unit length 'm' rotates with an angular velocity 'omega' in free space then :

A solid sphere with a velocity (of centre of mass) v and angular velocity omega is gently placed on a rough horizontal surface. The frictional force on the sphere :