Question
A thin horizontal circular disc is rotating about a vertical axis passing through its centre. An insect is at rest at a point near the rim of the d isc. The insect now moves along a diameter of the disc to reach its other end . During the journey of the insect, the angular speed of the disc.

Answer

As insect moves along a diameter, the effective mass and hence the $M.I.$ first decreases then increases so from principle of conservation of angular momentum, angular speed, first increases then decreases. 

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