Question

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

• A. $3m{a}^2$
• B. $2m{a}^2$
• C. $\frac{3}{4}m{a}^2$
• D. $\frac{3}{2}m{a}^2$

Answer 1

Answer: (C)

Moment of inertia of system about side $AB$ is

$I=m(0{)}^2+m(0{)}^2+m{\left(\frac{\sqrt{3}}{2}a\right)}^2$
$=\frac{3}{4}m{a}^2$