Question

an ant is sitting at the edge of a rotating disc. if the ant reaches the other end, after moving along the diameter the angular velocity of the disc will
a.remain constant b. Ist decrease &then increase
c. Ist decrease &then inc. d. inc. continuously

Answer 1

• The angular velocity of the disc will first increase than decrease.
• When ant is sitting on the edge of the rotating disc then from center distance if R .
• And we know that moment of inertia of disk is 1/2 MR²
• Now by applying the angular momentum conservation about the vertical axis this is passing from the center.
• Moment of inertia gets initially decrease and after that it get increase.
• And we know that angular velocity is ω =V/r.
• So from the above formula angular velocity will first increase than decrease.

Regards