System of Particles and Rotational Motion - Result Question 41
44. A round disc of moment of inertia $I_2$ about its axis perpendicular to its plane and passing through its centre is placed over another disc of moment of inertia $I_1$ rotating with an angular velocity $\omega$ about the same axis. The final
angular velocity of the combination of discs is
[2004]
(a) $\frac{(I_1+I_2) \omega}{I_1}$
(b) $\frac{I_2 \omega}{I_1+I_2}$
(c) $\omega$
(d) $\frac{I_1 \omega}{I_1+I_2}$
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Answer:
Correct Answer: 44. (d)
Solution:
- (d) Angular momentum will be conserved
$ I_1 \omega=I_1 \omega^{\prime}+I_2 \omega^{\prime} \Rightarrow \omega^{\prime}=\frac{I_1 \omega}{I_1+I_2} $
