On Fri, 15 Oct 2004, Rob Studdert wrote: > when a disc is spinning at 52x (ie 52x500RPM on the outside edge)
52 x 200 rpm actually. 200 rpm is the slowest speed a standard audio CD spins at (when reading the outermost track) and it is that speed that is used when quoting modern day large speed figures -- not the top speed used at the innermost track. The disc itself won't sustain the forces that 52 x 500 rpm would result in. The outer edge would travel at half the speed of sound, the force would be equal to 1500 g, and the hub would feel a tangential pull of 45 N/mm2. The disc would shatter. This Swedish language web page describes a full scale test, where CD:s were rotated at these speeds. When the disc breaked, the scrap almost penetrated a 1 mm aluminium cover. http://www.qedata.se/js_n-cdrom.htm anders ------------------------- http://anders.hultman.nu/ med dagens bild och allt!
