Question

Four identical rods each of mass $m$ and length $\ell$ make a square frame in $xy$ plane as shown. Calculate its moment of inertia about the $x$ -axis:-

• A. $\frac{5}{3}m{\ell }^2$
• B. $\frac{4}{3}m{\ell }^2$
• C. $m{\ell }^2$
• D. None of these

Answer 1

Answer: (A)

$I=I_1+I_2+I_3+I_4$
$=\frac{m{L}^2}{3}+\left(0+m{L}^2\right)+\frac{m{L}^2}{3}+0$
$I=\frac{5}{3}m{L}^2$