At 01:10 AM 9/25/99 +0100, you wrote: >Reply To: "Simon Redwood" >X-Mailer: ELM [version 2.4ME+ PL37 (25)] >MIME-Version: 1.0 >Content-Type: text/plain; charset=US-ASCII >Content-Transfer-Encoding: 7bit >Content-Length: 430 > > >But surely if 1-2 atoms were to hit you from behind would you not speed up >again ? > > I think its you hitting the atoms that would drain the energy. The atoms hitting you would, over time, have a net 0 effect on your rotational velocity. The atoms just sitting there, however, would be hit and sent screaming off in the other direction (with some tiny but probably measurable portion of your rotational K energy). Now granted, this has been happening to the planets in this solar system for several billion years, and they haven't stopped. It would take a real long time, but when you are talking about "perpetual" motion, a "real long time" is not very long (I'd think, in taking the broad view, it approaches zero... Don't spend too much time thinking about infinity, it stunts your growth. -Erik Reikes