A gramophone record is revolving with an angular velocity ?. A coin is placed at a distance r from the centre of the record. The static coefficient of friction is µ. The coin will resolve with the record if:

Options

(a) r = µ g ?ￂﾲ
(b) r (c) r (d) r >= µ g / ?ￂﾲ

Correct Answer:

r Explanation:

For the coin to revolve with the record, centrifugal force