Three rings each of mass $M$ and radius $R$ are arranged as shown in the figure. The moment of inertia of the system about the axis $YY'$ is:

$A$ solid sphere has mass $M$ and radius $R$. Its moment of inertia about a parallel axis passing through a point at a distance $R/3$ from its centre is:

Seven identical discs are arranged in a planar pattern,so as to touch each other as shown in the figure. Each disc has mass $m$ and radius $R$. What is the moment of inertia of the system of six outer discs about an axis passing through the centre of the central disc and normal to the plane of all discs?

Four holes of radius $R$ are cut from a thin square plate of side $4R$ and mass $M$. The moment of inertia of the remaining portion about the $z-$ axis is

Four solid spheres,each of diameter $\sqrt{5} \ cm$ and mass $0.5 \ kg$,are placed with their centers at the corners of a square of side $4 \ cm$. The moment of inertia of the system about the diagonal of the square is $N \times 10^{-4} \ kg \cdot m^2$. Find $N$.

From a uniform circular disc of radius $R$ and mass $9M$,a small disc of radius $\frac{R}{3}$ is removed as shown in the figure. The moment of inertia of the remaining disc about an axis perpendicular to the plane of the disc and passing through the centre of the original disc is