A thin horizontal circular disc is rotating about a vertical axis… - Vidyadip

MCQ

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.

A
continuously decreases
✓
continuously increases
C
first increases and then decreases
D
remains unchanged

✓

Answer

Correct option: B.

continuously increases

b
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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