Three rings each of mass M and radius R are arranged as shown in the figure. The moment of inertia of the system about YY¢ will be

Options

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

Answer

D

Explanation

M.I of system about YY. `I=I_(1)+I_(2)+I_(3)`
where `I_(1)` = moment of inertia of ring about diameter `l_(2)=l_(3)` = M.I. of inertia of ring about a tangent in a plane
`therefore I=(1)/(2)mR^(2)+(3)/(2)mR^(2)+(3)/(2)mR^(2)=(7)/(2)mR^(2)`