A gramophone record is revolving with an angular velocity ω. A coin is placed at a distance r from the centre of the record. The static coefficient of friction is μ. The coin will revolve with the record if :
Answer & explanation
Correct answer: option 4
\(\mu g \omega^2 \geq mr\omega^2\)
⇒ \(r \geq \frac{\mu g}{\omega^2}\)