A coin is placed on a gramophone record rotating at a speed of 45 rpm. It flies away when the rotational speed is 50 rpm. If two such coins are placed over the other on the same record, both of them will fly away when rotational speed is

Question

Dr. Abubacker · Accepted Answer

(d) A coin files off when centrifugal force just exceeds the force of friction $ie,$
$mr\omega^{2} \geq \mu mg$
or $\omega \geq \frac{\sqrt{\mu g}}{r}$
Thus $\omega^{\ }$does not depend upon mass and will remain the same

Q. A coin is placed on a gramophone record rotating at a speed of 45 rpm. It flies away when the rotational speed is 50 rpm. If two such coins are placed over the other on the same record, both of them will fly away when rotational speed is

Explanation

Reviewed by Dr. Abubacker

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