Q95 / 160 · JIPMER 2005 · Physics
Five particles of mass 2 kg are attached to the rim of a circular disc of radius 0.1 m and negligible mass. Moment of inertia of the system about the axis passing through the centre of the disc and perpendicular to its plane is
- A$1 \mathrm{~kg} \mathrm{~m}^2$
- Correct answerB$0.1 \mathrm{~kg} \mathrm{~m}^2$
- C$2 \mathrm{~kg} \mathrm{~m}^2$
- D$0.2 \mathrm{~kg} \mathrm{~m}^2$
Solution
The moment of inertia of the given system that contains 5 particles each of mass $=2 \mathrm{~kg}$ on the rim of circular disc of radius 0.1 m and of negligible mass is given by
$=\text { MI of disc }+ \text { MI of particle }$
Since the mass of the disc is negligible therefore, MI of the system $=$ MI of particle
$=5 \times 2 \times(0.1)^2=0.1 \mathrm{~kg} \mathrm{~m}^2$
Hence, the correct answer is option: 'B'.