Conservation in Expanding Sphere – Rankers Physics

Conservation in Expanding Sphere

A solid sphere is rotating freely about its symmetry axis in free space. The radius of the sphere is increased keeping its mass same. Which of the following physical quantities would remain constant for the sphere? (2018)

Rotational kinetic energy
Moment of inertia
Angular velocity
Angular momentum

Solution:

In the absence of any external torque acting on the sphere in free space, the angular momentum of the system remains conserved. Therefore, angular momentum remains constant while moment of inertia increases and angular velocity decreases.

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