A small coin is placed at a distance r from the centre of a gramophone record. The rotational speed of the record is gradually increased. If the coefficient of friction between the coin and the record is μ, the minimum angular frequency of the record for which the coin will fly off is given by
1
\(\sqrt{\frac{2 \mu \mathrm{g}}{\mathrm{r}}}\)
2
\(\sqrt{\frac{\mu g}{2 r}}\)
3
\(\sqrt{\frac{\mu \mathrm{g}}{\mathrm{r}}}\)
4
\(2 \sqrt{\frac{\mu g}{r}}\)