The ratio of radii of gyration of a thin circular ring and a circular disc of same radius about a tangential axis in their own planes is $\sqrt{12}: \sqrt{K}$. The value of $K$ is

A thin uniform circular disc of mass $\frac{10}{\pi^2} \mathrm{~kg}$ and radius 2 m is rotating about an axis passing through its centre and perpendicular to its plane. The work done to increase the angular speed of the disc from $90 \mathrm{rev} / \mathrm{min}$ to $120 \mathrm{rev} / \mathrm{min}$ is

Due to global warming, if the ice in the polar region melts and some of this water flows to the equatorial region, then