$A$ swimmer curls their body before diving into the water from a height so that:

Two discs $A$ and $B$ of same material and thickness have radii $R$ and $3R$ respectively. Their moments of inertia about their axis will be in the ratio

Four solid spheres,each of mass $M$ and radius $R$,are placed at the four corners of a square of side length $a$. Find the moment of inertia of the system about an axis coinciding with one of the sides of the square.

The moment of inertia of a uniform thin rod of mass $m$ and length $\ell$ about a perpendicular axis passing through one end is $I_{1}$. The same rod is bent into a ring and its moment of inertia about a diameter is $I_{2}$. If $\frac{I_{1}}{I_{2}} = \frac{x \pi^{2}}{3}$,then the value of $x$ will be ...............

Two discs,one of density $7.2 \, g/cm^3$ and the other of density $8.9 \, g/cm^3$,have the same mass and thickness. What is the ratio of their moments of inertia?

Two circular loops $P$ and $Q$ are made from a uniform wire. The radii of $P$ and $Q$ are $R_1$ and $R_2$ respectively. The moments of inertia about their own axis are $I_{P}$ and $I_{Q}$ respectively. If $\frac{I_{P}}{I_{Q}}=\frac{1}{8}$,then $\frac{R_2}{R_1}$ is