$A$ 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

Three particles are situated on a light and rigid rod along the $Y$-axis as shown in the figure. If the system is rotating with an angular velocity of $2 \, rad/s$ about the $X$-axis,then the total kinetic energy of the system is ...... $J$.

$A$ ring of mass $10 \ kg$ and radius $0.5 \ m$ is rotating about its diameter with an angular velocity of $20 \ rad/s$. Its rotational kinetic energy is .......... $J$.

$A$ kathak dancer is standing on a horizontal surface with folded hands. Initially, the dancer is rotating about his central axis, and his kinetic energy is $K$. The dancer then stretches his arms such that the moment of inertia becomes three times its initial value and the angular velocity becomes one-third of its initial value. The kinetic energy of the dancer now is:

$A$ 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 ....... $J$.

$A$ uniform thin rod of length $l$ and mass $m$ is suspended from one of its ends and is rotated at $f$ rotations per second. The rotational kinetic energy of the rod will be