Question

If a person sitting on a rotating stool with his hands outstretched, suddenly lowers his hands, then his :

• A. Kinetic energy will decrease.
• B. Moment of inertia will decrease.
• C. Angular momentum will increase.
• D. Angular velocity will remain constant.

Answer 1

The correct option is B Moment of inertia will decrease.

According to conservation of Angular Momentum,
$I\omega$ = constant
Hence, when a person sitting on a rotating stool suddenly lowers his hands, then his angular velocity will increase and moment of inertia will decrease.