The diameter of a long playing vinyl record is 12 inches. The unused center has a diameter of 4 inches, and there is a smooth outer edge that is 1 inch wide. If there are 91 grooves to the inch, how far does the needle travel within the groove during playback of the record?

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I would worry that the fact that it was one archimedian spiral rather than 273 concentric circles would change the amount enough so that precision to the millionth of an inch would be overly precise.

Posted by Charlie on 2005-03-31 19:38:11