Question:
An massless equilateral triangle EFG of side 'a' (As shown in figure) has three particles of mass $\mathrm{m}$ situated at its vertices. The moment of intertia of the system about the line EX perpendicular
to $\mathrm{EG}$ in the plane of $\mathrm{EFG}$ is $\frac{\mathrm{N}}{20} \mathrm{ma}^{2}$ where $\mathrm{N}$
is an integer. The value of $\mathrm{N}$ is__________.
Solution:
$\mathrm{I}=0+\mathrm{m}\left(\frac{\mathrm{a}}{2}\right)^{2}+\mathrm{ma}^{2}$
$=\frac{5}{4} \mathrm{ma}^{2}$