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