$A$ body completes one rotation in $1 \ s$. What is its moment of inertia if its rotational kinetic energy is $E_R$?

$A$ flywheel is in the form of a solid circular disc of mass $72 \ kg$ and radius of $0.5 \ m$. If it rotates at $70 \ r.p.m.$,then the rotational kinetic energy is approximately ....... $J$.

$A$ solid cylinder of mass $M$ and radius $R$ is rotating about its geometrical axis. $A$ solid sphere of same mass and same radius is also rotating about its diameter with an angular speed half that of the cylinder. The ratio of the kinetic energy of rotation of the sphere to that of the cylinder will be

$A$ solid sphere of mass $M$ and radius $R$ is rotating about its diameter. $A$ disc of the same mass and radius is also rotating about an axis passing through its centre and perpendicular to the plane,but its angular speed is twice that of the sphere. The ratio of the kinetic energy of the disc to that of the sphere is: (in $: 1$)

Two bodies have their moments of inertia $I$ and $2I$ respectively about their axis of rotation. If their kinetic energies of rotation are equal,their angular momentum will be in the ratio

$A$ body is rotating about its own axis. Its rotational kinetic energy is $x$ and its angular momentum is $y$. Hence,its moment of inertia about its own axis is: