Consider only one side of the record.
Clearly the length of the groove is a function of groove width and the area of the resulting annulus of grooves. The area of the annulus being the difference between the 4 inch diameter center circle and the 10 inch diameter circle to the outside groove, or, 25pi - 4pi = 21pi. So, the length of the groove is ...
21pi times 91 = 1911pi or 6003.583561 inches
Posted by CeeAnne
on 2005-03-31 19:26:45