The moment of inertia of a door of mass `m`, length `2 l` and width `l` about its longer side is.

Options

A. `(11ml^(2))/24`
B. `(5ml^(2))/24`
C. `(ml^(2))/3`
D. none of these

Answer

C

Explanation

(About `Y Y^(h)`) `=(ml^(2))/12`
Using parallel axis theorem,
`I` (about `AD`) `=(ml^(2))/12+(ml^(2))/4=(ml^(2))/3`