Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84; site ritcv.UUCP Path: utzoo!watmath!clyde!burl!ulysses!allegra!mit-eddie!godot!harvard!seismo!rochester!ritcv!jeh From: jeh@ritcv.UUCP (Jim Heliotis) Newsgroups: net.movies Subject: Re: 2010 mistakes/non-mistakes Message-ID: <1457@ritcv.UUCP> Date: Thu, 3-Jan-85 11:28:37 EST Article-I.D.: ritcv.1457 Posted: Thu Jan 3 11:28:37 1985 Date-Received: Fri, 4-Jan-85 05:11:16 EST References: <1575@qubix.UUCP> <289@wjvax.UUCP> <2456@CSL-Vax.ARPA> Organization: Rochester Institute of Technology, Rochester, NY Lines: 23 > > Mark Callow mentioned that there is a difference between > > 'zero gravity' and 'free fall'. I give up. What is it? > > Zero g == zero gravities == no acceleration == free fall > > "Zero gravity" is meaningless, because gravity obeys the inverse-square law, > and is not blocked by anything. Hence, everywhere in the universe there is > some gravitational influence. What does this mean!? "g" = The force you feel on the surface of the earth (thus you feel > 1 g when taking off in a rocket). This means that 0 g means you feel no "force" pulling on you. Free fall is just one way to feel 0 g, and it certainly does not mean no acceleration, it means you are accelerating unhindered by by any source of friction/damping. The other way to feel (close to) 0 g is to be 'far' away from any other mass. Another way might be near masses where the vector sum of their gravi- tational forces equals 0, but even this is only approximate, since everyone has finite volume, and the equilibrium point is just a single point, or perhaps a line or plane.