Question

Four particles each of mass $M$ are placed at the corners of a square of side length $l$.The moment of inertia of four bodies about an axis passing through any side of the frame 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 $2M{L}^2$

MI of system about any side will have contribution from two masses which are not on this axis, so

$I=2\times M{l}^2=2M{l}^2$