A circular disc is rotating in horizontal plane about vertical axis passing through its centre without friction with a person standing on a disc at its edge. If the person gently walks to the centre of disc its angular velocity

A circular disc is rotating about an axis along horizontal plane with a

person standing at an edge with an angular velocity

*Obviously possess greater moment inertia$I_1$

Let angular velocity$={\omega }_1$ 

*As the person walk closer to centre then mass will be more concentrated closer to axis hence moment of inertia decreases then$I_2<I_1$

By law of conservation of angular momentum

$I_1{\omega }_1=I_2{\omega }_2$ 

Now we can have

${\omega }_1<{\omega }_2\because I_1>I_2$

So angular velocity increases