Q. Three identical thin rods each of length $l$ and mass $M$ are joined together to form a letter $H$. What is the moment of inertia of the system about one of the sides of $H$?
A) $M\frac{l^{2}}{4}$
B) $M\frac{l^{2}}{3}$
C) $2\ \frac{{Ml}^{2}}{3}$
D) $4\frac{Ml^{2}}{3}$
Explanation
(d) Moment of inertia of the system about rod $x$, figure
[image:7_image128.emf]
$I = I_{x} + I_{y} + I_{\mathcal{z}} = 0 + \left( \frac{Ml^{2}}{12} + \frac{Ml^{2}}{4} \right) + Ml^{2}$
$= \frac{4}{3}Ml^{2}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.