Class 11 NEET Physics System of Particles and Rotational Motion

Moment of inertia for the rod AB rotating about an axis through the midpoint of AB perpendicular to the plane of the paper is

Ml2

12

∴ M.I. about the axis passing through the center of the square and parallel to this axis,
I=I0+Md2=M(

l2

12

+

l2

4

)=

Ml2

3

For all the four rods,I=

4

3

Ml2