Moment of inertia of a disc of radius R about a diametric axis is `35 "kg m"^(-2)`. The `MI` of the disc about a parallel axis at a distance `R//2` from the centre is

Options

A. `31.25 "kg-m"^(2)`
B. `37.5 "kg-m"^(2)`
C. `50 "kg-m"^(2)`
D. `62.5 "kg-m"^(2)`

Answer

B

Explanation

Moment of inertia of a disc about a parallel axis
`I=I_(v)+md^(2)=(ma^(2))/(2)+md^(2)" "(because a=R,d=R)`
`rArr` Moment of inertia `= (3)/(2) ma^(2)=(3)/(2)(25)`
`:.` Moment of inertia `= (75)/(2)=37.5 "kg m"^(-2)`.