Three point masses, each of mass `m`, are placed at the corners of an equilateral triangle of side `L`. The moment of inertia of this system about an axis along one side of the triangle is

Options

A. `3ml_(2)`
B. `(3)/(2)ml^(2)`
C. `ml^(2)`
D. `(3)/(4)ml^(2)`

Answer

D

Explanation

Distance of corner mass from opposite side,
`r=sqrt(l^(2)-(l//2)^(2))=(sqrt3)/(2)l`
`"and "l=mr^(2)=(3)/(4)ml^(2)`