Thank you for reporting, we will resolve it shortly
Q.
If frictional force is neglected and girl bends her hand, then (initially girl is rotating on chair)
System of Particles and Rotational Motion
Solution:
As there is no external torque, so if the girl bends her hands, her moment of inertia about the rotational axis will decrease. By conservation of angular momentum, $L=I \omega=$ constant. So in order to keep $L$ constant, if $I$ is decreasing, then $\omega$ will increase.
