Three particles, each of mass `m` grams situated at the vertices of an equilateral triangle `AbC` of side `I` cm (as shown in the figure). The moment of inertia of the system about a line `AX` perpendicular to `AB` and in the plane of `ABC`, in gram-cm^2 units will be.
.

Options

A. `(3)/(4) ml^(2)`
B. `2ml^(2)`
C. `(5)/(4) ml^(2)`
D. `(3)/(2) ml^(2)`

Answer

C

Explanation

`I= m(l)^(2) + m ((l)/(2))^(2)= (5)/(4) ml^(2)`