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A coin is placed on a vinyl stereo record that is making 33 1/3 revolutions per minute on a turntable.?

February 21st, 2010 by admin

A coin is placed on a vinyl stereo record that is making 33 1/3 revolutions per minute on a turntable.

(a) Find the magnitude of the acceleration when the coin is placed 5.0, 10, and 14 cm from the center of the record.

(b) At which of the three radii listed in part (a) would the coin be most likely to fly off the turntable? Why?

For convenience, convert the given 33.3rev min to rad/s :

33.3rev/min(2πrad/rev)(1.00min/60.0s) = 3.49rad/s

Now, the tangential speed is v = rω and acceleration is a = v² / r. So the acceleration after substitution is :

a = (rω)² / r
= rω²

Then for (a) :

a = 5.00cm(3.49rad/s)² = 60.9cm/s²

a = 10.0cm(3.49rad/s)² = 122cm/s²

a = 14.0cm(3.49rad/s)² = 171cm/s²

(b) Most likely the coin would fly off the turntable when the coin was located at 14.0vm from the center because there is a higher acceleration at that point. Since the force on the coin there would be the acceleration multiplied by the coin’s mass (and after the force of friction between the coin and surface was subtracted from this force), would be greater than at the other two points.

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One Response to “A coin is placed on a vinyl stereo record that is making 33 1/3 revolutions per minute on a turntable.?”

  1. #1
    Algol
    February 21st, 2010 6:48 pm

    For convenience, convert the given 33.3rev min to rad/s :

    33.3rev/min(2πrad/rev)(1.00min/60.0s) = 3.49rad/s

    Now, the tangential speed is v = rω and acceleration is a = v² / r. So the acceleration after substitution is :

    a = (rω)² / r
    = rω²

    Then for (a) :

    a = 5.00cm(3.49rad/s)² = 60.9cm/s²

    a = 10.0cm(3.49rad/s)² = 122cm/s²

    a = 14.0cm(3.49rad/s)² = 171cm/s²

    (b) Most likely the coin would fly off the turntable when the coin was located at 14.0vm from the center because there is a higher acceleration at that point. Since the force on the coin there would be the acceleration multiplied by the coin’s mass (and after the force of friction between the coin and surface was subtracted from this force), would be greater than at the other two points.
    References :

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