Question

A diver folds himself close to his axis of rotation while diving down.
A) Angular momentum of diver remains constant.
B) Rotational kinetic energy of diver increases.

• A. A and B both are true
• B. A and B both are false
• C. only A is true
• D. only B is true

Answer 1

The correct option is A A and B both are true

Net external torque is zero, $\therefore$ Angular momentum will remain conserved.
$\therefore I_1{\omega }_1=I_2{\omega }_2$
Moment of Inertia will decrease, because more mass is directed towards centre,
$\therefore \omega$ will increase
$\therefore$ Rotational kinetic energy will increase.