JEE Mains · Physics · STD 11 - 6. system of particles and rotational motion
Three balls of masses \(2 \mathrm{~kg}, 4 \mathrm{~kg}\) and \(6 \mathrm{~kg}\) respectively are arranged at centre of the edges of an equilateral triangle of side \(2 \mathrm{~m}\). The moment of inertia of the system about an axis through the centroid and perpendicular to the plane of triangle, will be _______\(\mathrm{kg} \mathrm{m}{ }^2\).
- A \(5\)
- B \(8\)
- C \(7\)
- D \(4\)
Answer & Solution
Correct Answer
(D) \(4\)
Step-by-step Solution
Detailed explanation
Moment of inertia about \(\mathrm{C}\) and perpendicular to the plane is: \(\mathrm{I} =\mathrm{r}^2[2+4+6]\) \(=\frac{1}{3} \times 12\) \(\mathrm{I} =4 \mathrm{~kg}-\mathrm{m}^2\)
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