Question

The moment if inertia of a uniform circular disc about its diameter is 100g cm² what is its moment of inertia (a)about its tangent and (b)about an axis perpendicular to the plane.

Answer 1

Answer:

b is correct

Explanation:

We know, moment of inertia of a uniform circular disc of mass M and radius R about an axis passing through centre is given by,

I_{\textbf{centre}}=\frac{1}{2}MR^2

from perpendicular axis theorem,

moment of inertia of disc about a diameter , I_{\textbf{diameter}}=\frac{I_{\textbf{centre}}}{2}

a/c to question, it is given that, moment of inertia of disc about a diameter is I

then, I=\frac{1}{2}I_{\textbf{centre}}=\frac{1}{4}MR^2

so, MR^2=4I........(1)

now, we have to find moment of inertia about an axis perpendicular to its plane and passing through a point on its rim.

use parallel axis theorem,