Question

Four point size bodies each of mass $M$ are fixed at four corners of a light square frame of side length $L$. The moment of inertia of the four bodies about an axis perpendicular to the plane of frame and passing through its center is:

• A. $4M{L}^2$
• B. $2\sqrt{2}M{L}^2$
• C. $2M{L}^2$
• D. $\sqrt{2}M{L}^2$

Answer 1

The correct option is C $2M{L}^2$

$I=4\times M(\frac{\sqrt{2}L}{2}{)}^2$ since distance of the point mass from center is half of the diagonal.

$\Rightarrow I=2M{L}^2$