Q. 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 disc. The insect now moves along a diameter of the disc to reach other end. During the journey of the insect, the angular speed of the disc
A) Remains unchanged
B) Continuously decreases
C) Continuously increases
D) First increases and then decreases
Explanation
(d) [image:7_image141.emf]
From angular momentum conservation about vertical axis passing through centre. When insect is coming from circumference to centre. Moment of inertia first decrease then increase. So angular velocity increase then decrease
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.