question_answer

A gramophone record is revolving with an angular velocity \[\omega .\] A coin is placed at a distance r from the center of the record. The static coefficient of friction is \[\mu .\]The coin will revolve with the record if

A)   \[r<\frac{\mu g}{{{\omega }^{2}}}\]only           

B)  \[r>\frac{\mu g}{{{\omega }^{2}}}\]only

C)  \[r=\frac{\mu g}{{{\omega }^{2}}}\]only             

D)  \[r\le \frac{\mu g}{{{\omega }^{2}}}\]only