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From: jlg@lanl-a.UUCP
Newsgroups: net.physics
Subject: Re:  Dean Drive Possible?
Message-ID: <7280@lanl-a.UUCP>
Date: Mon, 14-May-84 15:06:00 EDT
Article-I.D.: lanl-a.7280
Posted: Mon May 14 15:06:00 1984
Date-Received: Wed, 16-May-84 04:00:11 EDT
References: <683@sri-arpa.UUCP>
Organization: Los Alamos National Laboratory
Lines: 11

iiii

It IS possible to change orientation without effecting angular momentum or
any other momentum.  By change of orientation I mean 'face the other way' or
'turn around' relative to distant reference points.  Scientific American had 
an article on this a couple of years ago (I don't remember the date).  The
main application cited in the article was Diving (off a diving board, olympics,
that kind of stuff).  A diver does a twist by counter-rotating various parts 
of his body and then bringing such relative motions to a stop again,  but now
his body as a whole is in a different orientation.  The net angular momentum
of his body never changed - and could have been ZERO.