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A gramophone record is revolving with an...

A gramophone record is revolving with an angular velocity `omega`. A coin is placed at a distance `R` from the centre of the record. The static coefficient of friction is `mu`. The coin will revolve with the record if

A

`r= mu gomega ^(2)`

B

`r lt (omega^(2))/(mu g)`

C

`r le (mu g) /(omega^(2))`

D

`r ge (mu g)/(omega^(2))`

Text Solution

Verified by Experts

The correct Answer is:
C
Here friction force provides centripetal force so
`f=m omega^(2)r "but" fle mu mg`
So`momega^(2)rle mu mg implies rle(mu g)/(omega^(2))`
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