A gramophone record is revolving with an angular velocity ?. A coin is placed at

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A gramophone record is revolving with an angular velocity ?. A coin is placed at a distance r from the centre of the record. The static coefficient of friction is µ. The coin will resolve with the record if:

Options

(a) r = µ g ?ￂﾲ
(b) r < ?ￂﾲ / µ g
(c) r <= µ g / ?ￂﾲ
(d) r >= µ g / ?ￂﾲ

Correct Answer:

r <= µ g / ?ￂﾲ

Explanation:

For the coin to revolve with the record, centrifugal force <= frictional force mr ?ￂﾲ <= µ mg r <= µg / ?ￂﾲ

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Topics: Motion of system of Particles and Rigid Body (73)
Subject: Physics (2479)

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