Rankers Physics

Angular Momentum and Conservation of Angular Momentum: Practice Problem & Solution

A disc is rotating with angular speed $\omega$. If a child sits on it, what is conserved: (2002)
Linear momentum
Angular momentum
Kinetic energy
Potential energy

Solution Explained:

To solve this problem, we apply the core principles of Angular Momentum and Conservation of Angular Momentum. Understanding the underlying formula is key to arriving at the correct answer below:

When the child sits on the rotating disc gently, no external torque acts on the system.
According to Newton's second law for rotation, if net external torque is zero, the total angular momentum of the system remains conserved.

Leave a Reply

Your email address will not be published. Required fields are marked *

Similar Practice Questions

Explore conceptually related problems to test your knowledge.

1. Assertion (A): In case of rolling without sliding, friction force can act in forward and backward direction both. Reason (R): The angular momentum of a system will be conserved only about that point about which external angular impulse is zero.  
2. What is moment of inertia in terms of angular momentum (L) and kinetic energy (K)
3. From a circular ring of mass \(M\) and radius \(R\) an arc corresponding to a \(90^\circ\) sector is removed. The moment of inertia of the remaining part of the ring about an axis passing through the centre of the ring and perpendicular to the plane of the ring is \(K\) times \(MR^2\). Then the value of \(K\) is
4. The instantaneous angular position of a point on a rotating wheel is given by the equation $$\theta (t) = 2t^{3} - 6t^{2}$$. The torque on the wheel becomes zero at: (2011 Pre)
5. A solid cylinder of mass $M$ and radius $R$ rolls without slipping down an inclined plane of length $L$ and height $h$. What is the speed of its centre of mass when the cylinder reaches its bottom: (2003)