A solid sphere is in rolling motion. In rolling motion a body possesses translational kinetic energy $(K_t)$ as well as rotational kinetic energy $(K_r)$ simultaneously. The ratio $K_t : (K_t + K_r)$ for the sphere is
$7:10$
$5:7$
$2:5$
$10:7$
If a body completes one revolution in $\pi $ $sec$ then the moment of inertia would be
Rotational kinetic energy of a given body about an axis is proportional to
A circular disc has a mass of $1\ kg$ and radius $40\ cm$. It is rotating about an axis passing through its centre and perpendicular to its plane with a speed of $10\ rev/s$. The work done in joules in stopping it would be ...... $J$
Write the formula for rotational kinetic energy.
A cord is wound round the circumference of wheel of radius $r$. The axis of the wheel is horizontal and the moment of inertia about it is $I. \,A$ weight $mg$ is attached to the cord at the end. The weight falls from rest. After falling through a distance $ 'h '$, the square of angular velocity of wheel will be ..... .