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

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

$A$ spherical solid ball of $1\,kg$ mass and radius $30\,cm$ is rotating about an axis passing through its centre with an angular velocity of $50\,rad/s$. The kinetic energy of rotation is ......... $J$.

$A$ flywheel rotating about a fixed axis has a kinetic energy of $500 \text{ J}$. If its angular frequency is $5 \text{ Hz}$, calculate the moment of inertia of the wheel about the axis of rotation. (Take $\pi^2 = 10$) (in $\text{ kg m}^2$)

$A$ 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:

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