Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 (Tek) 9/28/84 based on 9/17/84; site tektronix.UUCP Path: utzoo!watmath!clyde!burl!ulysses!allegra!bellcore!decvax!tektronix!carlc From: carlc@tektronix.UUCP (Carl Clawson) Newsgroups: net.physics Subject: Re: Re: Non-linear systems. Message-ID: <4781@tektronix.UUCP> Date: Tue, 15-Jan-85 11:31:58 EST Article-I.D.: tektroni.4781 Posted: Tue Jan 15 11:31:58 1985 Date-Received: Thu, 17-Jan-85 04:19:50 EST References: <209@talcott.UUCP> <328@rlgvax.UUCP> <384@hou2g.UUCP> <1027@sunybcs.UUCP> <386@hou2g.UUCP> Reply-To: carlc@tektronix.UUCP (Carl Clawson) Organization: Tektronix, Beaverton OR Lines: 21 Summary: In article <386@hou2g.UUCP> stekas@hou2g.UUCP (J.STEKAS) writes: >Randomness and predictability are two different things. Randomness >is sufficient for unpredictability but not the only source. > >In linear types of systems, like Newtonian orbital mechanics, >one can easily show that intitial states which are infinitesimally >different at t=0 will be infinitesimally different at t=T. Sorry, but Newtonian mechanics is not necessarily linear. (I'm assuming you're referring to the equation of motion F=ma.) For Newtonian gravity F is proportional to 1/(r**2), thus the non-linear equation 2 2 2 d r/dt = constant x 1/(r ) Linearity is not necessary for "predictability" as described in the referenced article. Carl Clawson ...tektronix!carlc