Two identical concentric rings each of mass (m) and radius (r ) placed perpendicularly. So the moment of inertia about axis of one of the ring is …………..

Options

A. `(1)/(2)mr^(2)`
B. `mr^(2)`
C. `(3)/(2)mr^(2)`
D. `2mr^(2)`

Answer

C

Explanation

`I_(1)` = Moment of inertia about diameter = `(1)/(2)mr^(2)`
`I_(2)` = Moment of inertia about axis passing through centre and perpendicular to plane = `mr^(2)`
`I=I_(1)+I_(2)=(1)/(2)mr^(2)+mr^(2)=(3)/(2)mr^(2)`