The figure shows two solid discs with radius $R$ and $r$ respectively. If mass per unit area is the same for both, what is the ratio of $M I$ of bigger disc around axis $A B$ (Which is $⊥$ to the plane of the disc and passing through its centre) of $M I$ of smaller disc around one of its diameters lying on its plane? Given $M$ is the mass of the larger disc.
( $M I$ stands for a moment of inertia)

Question

The figure shows two solid discs with radius $R$ and $r$ respectively. If mass per unit area is the same for both, what is the ratio of $M I$ of bigger disc around axis $A B$ (Which is $⊥$ to the plane of the disc and passing through its centre) of $M I$ of smaller disc around one of its diameters lying on its plane? Given $M$ is the mass of the larger disc.

( $M I$ stands for a moment of inertia)

Aicharya · Accepted Answer

Ratio of the moment of inertia = 1 2 M R 2 1 4 m r 2 = 2 &#963;&#960; R 2 R 2 &#963; &#960; r 2 r 2 = 2 R 4 r 4

The figure shows two solid discs with radius R and r respectively. If mass per unit area is the same for…

Solution