System of Particles and Rotational Motion - Result Question 43
46. A disc is rotating with angular velocity $\omega$. If a child sits on it, what is conserved ?
[2002]
(a) Linear momentum
(b) Angular momentum
(c) Kinetic energy
(d) Moment of inertia
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Answer:
Correct Answer: 46. (b)
Solution:
- (b) If external torque is zero, angular momentum remains conserved.
$L=I \omega=$ constant
External torque is zero because the weight of child acts downward
