Question

A solid sphere is rotating in free space. If the radius of the sphere is increased keeping mass same which one of the following will not be affected ?(a) Angular velocity(b) Angular momentum(c) Moment of inertia(d) Rotational kinetic energy

Answer 1

d. Rotational kinetic energy

Answer 2

Law of conservation of angular moment -

\vec{\tau }= \frac{\vec{dL}}

- wherein

If net torque is zero

i.e. \frac{\vec{dL}}= 0

\vec{L}= constant

angular momentum is conserved only when external torque is zero .

Angular momentum remains constant

i.e. \vec{\tau_{ext}}=0

Option 1)

moment of inertia

This is an incorrect option.

Option 2)

angular momentum

This is the correct option.

Option 3)

angular velocity

This is an incorrect option.

Option 4)

rotational kinetic energy

This is an incorrect option.