Question:
Consider a uniform wire of mass $M$ and length L. It is bent into a semicircle. Its moment of inertia about a line perpendicular to the plane of the wire passing through the centre is :
Correct Option: , 3
Solution:
$\pi \mathrm{r}=\mathrm{L} \Rightarrow \mathrm{r}=\frac{\mathrm{L}}{\pi}$
$\mathrm{I}=\mathrm{Mr}^{2}=\frac{\mathrm{ML}^{2}}{\pi^{2}}$