Q. Two masses of 200 g and 300 g are attached to the 20 cm and 70 cm marks of a light metre rod respectively. The moment of inertia of the system about an axis passing through 50 cm mark is
A) $0.15\ kg\ m^{2}$
B) $0.03\ kg\ m^{2}$
C) $0.3\ kg\ m^{2}$
D) Zero
Explanation
(b) $I = m_{1}r_{1}^{2} + m_{2}r_{2}^{2}$
$= \frac{200}{1000}\ \left( \frac{30}{100} \right)^{2} + \frac{300}{1000}\left( \frac{20}{100} \right)^{2} = 0.03\ kg\ m^{2}$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.