Question

The moment of inertia of a uniform circular disc about its diameter is 200 gm $c{m}^2$. Then its moment of inertia about an axis passing through its center and perpendicular to its circular face is

• A. 100 gm $c{m}^2$
• B. 200 gm $c{m}^2$
• C. 400 gm $c{m}^2$
• D. 1000 gm $c{m}^2$

Answer 1

The correct option is C 400 gm $c{m}^2$

Moment of inertia of the disc about its diameter is half of the moment of inertia of disc about its center of mass and perpendicular to its plane.

Given : $I_{diameter}=200gmc{m}^2$

$\therefore$ $I_{diameter}=\frac{1}{2}\times I_{C}M$

$⟹I_{CM}=2I_{diameter}=2\times 200=400gmc{m}^2$