Let $M$ be the mass and $L$ be the length of a thin uniform rod. In the first case,the axis of rotation passes through the center and is perpendicular to the length of the rod. In the second case,the axis of rotation passes through one end and is perpendicular to the length of the rod. The ratio of the radius of gyration in the first case to the second case is

$A$ metallic solid sphere is rotating about its diameter as an axis of rotation. If the temperature is increased by $200^{\circ} C$, the percentage increase in its moment of inertia is (Coefficient of linear expansion of the metal $= 10^{-5} /^{\circ} C$) (in $\%$)

Four hollow spheres,each with a mass of $1\, kg$ and a radius $R = 10\, cm$,are connected with massless rods to form a square with a side of length $L = 50\, cm$. In case-$1$,the masses rotate about an axis that bisects two sides of the square. In case-$2$,the masses rotate about an axis that passes through the diagonal of the square,as shown in the figure. Compute the ratio of the moments of inertia $I_1/I_2$ for the two cases.

Two circular loops $A$ and $B$ of radii $R$ and $NR$ respectively are made from a uniform wire. The moment of inertia of $B$ about its axis is $3$ times that of $A$ about its axis. The value of $N$ is:

Point masses of $1, 2, 3,$ and $4 \ kg$ are placed at $(0, 0, 0), (2, 0, 0), (0, 3, 0),$ and $(-2, -2, 0)$ respectively. What is the moment of inertia of this system about the $x$-axis in $kg-m^2$?

Write the practical uses of moment of inertia.