Three rings, each of mass `m` and radius `r`, are so placed that they touch each other. Find the moment of inertia about the axis as shown in Fig.

Options

A. `3MR^(2)`
B. `3/2 MR^(2)`
C. `5MR^(2)`
D. `7/2 MR^(2)`

Answer

D

Explanation

`I=(MR^(2))/2+2[3/2MR^(2)]=(MR^(2))/2+3MR^(2)=(7MR^(2))/2`