If a gymnast, sitting on a rotating stool with his arms outstretched, suddenly lowers his hands.

Question

If a gymnast, sitting on a rotating stool with his arms outstretched, suddenly lowers his hands. (A) The angular velocity decreases (B) His momentum of inertia decreases (C) The angular velocity stays constant (D) The angular momentum increases

Tardigrade Admin · Accepted Answer

As the gymanst lowers his hands, the radius of gyration decreases and hence moment of inertia also decreases. Angular momentum remains conserved and hence angular velocity increases.

Q. If a gymnast, sitting on a rotating stool with his arms outstretched, suddenly lowers his hands.

The angular velocity decreases

His momentum of inertia decreases

The angular velocity stays constant

The angular momentum increases

As the gymanst lowers his hands, the radius of gyration decreases and hence moment of inertia also decreases. Angular momentum remains conserved and hence angular velocity increases.