PYQ NEET- Rotational Motion L-10
Question: A disc is rotating with angular velocity $\omega$. If a child sits on it, what is conserved?
A) Linear momentum
B) Angular momentum
C) Kinetic energy
D) Moment of inertia
Answer: Angular momentum
Solution:
If no external torque is applied on the system, then angular momentum of the system remains constant. When a child sits on rotating disc, then no torque is applied (weight of child acts downward) so angular momentum will remain conserved.