JEE Mains · Physics · STD 11 - System of particles and rotational motion
- JEE Mains 2024
- Hard
- MCQ
A thin circular disc of mass \(M\) and radius \(R\) is rotating in a horizontal plane about an axis passing through its centre and perpendicular to its plane with angular velocity \(\omega\). If another disc of same dimensions but of mass \(\mathrm{M} / 2\) is placed gently on the first disc co-axially, then the new angular velocity of the system is _______.
Pick an option to check your answer.
Answer & Solution
Correct Answer
(C) \(\frac{2}{3} \omega\)
Step-by-step Solution
Detailed explanation
\(\mathrm{I}_1 \omega=\mathrm{I}_2 \omega_2\)
\(\frac{\mathrm{MR}^2}{2} \omega=\frac{3}{2}\left(\frac{\mathrm{MR}^2}{2}\right) \omega_2\)
\(\omega_2=\frac{2}{3} \omega\)
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