A thin wire of length L and uniform linear mass density ρ is bent into a circular loop with centre at O as shown. The moment of inertia of the loop about the axis XX ' is
(4)
About the diameter of the circular loop (ring)
I=12MR2
Using parallel axis theorem
Moment of inertia of the loop about XX' axis
Ixx'=MR22+MR2=32MR2
Here mass M=Lρ and radius R=L2π;
∴ Ixx'=32(Lρ)(L2π)2=3L3ρ8π2