From: "Clive Tooth" Subject: Re: wobbling cylinders Date: Fri, 12 May 2000 09:03:26 +0100 Newsgroups: sci.math,sci.physics Summary: [missing] Michael McGuffin wrote in message <8ffhu5$sa$2@watserv3.uwaterloo.ca>... >Anyone have any references or URLs that describe how >to model a wobbling cylinder ? For example, a coin >that is set spinning on its edge on a table top >will eventually slow down and start wobbing. The >wobbling seems to increase in frequency as the coin's >center of gravity gets lower and lower. What's >going on here ? Is the edge of the coin gradually slipping >outward (dynamic friction) ? Ideally, I would like >enough information to simulate this on a computer >with fairly good accuracy. There was a recent article in Nature about this... ================================================== 20 April 2000 Nature 404, 833 - 834 (2000) © Macmillan Publishers Ltd. Euler's disk and its finite-time singularity H. K. MOFFATT Isaac Newton Institute for Mathematical Sciences, 20 Clarkson Road, Cambridge CB3 0EH, UK e-mail: hkm2@newton.cam.ac.uk ================================================== Air viscosity is apparently an important factor in the behaviour of the disk. I would be interested to know of any observations of such a disk spinning in a vacuum. The URL of the Nature article is http://www.nature.com/cgi-taf/DynaPage.taf?file=/nature/journal/v404/n6780/f ull/404833a0_fs.html but you may not be able to access it unless you have a subscription. See also: http://www.tangenttoy.com/edisk.html [sci.physics added to Newsgroups] -- Clive Tooth http://www.pisquaredoversix.force9.co.uk/ End of document