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Article #6291Re: Difference between physics and mathematics
From: Pentcho Valev
Date: Sun, 14 Oct 2007 14:01
Date: Sun, 14 Oct 2007 14:01
30 lines
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3321 bytes
On 14 Oct, 03:15, Tom Roberts <tjroberts...@sbcglobal.net> wrote: > Juan R. wrote: > > In Newtonian theory, gravity is a real force whereas the two first > > [centrifugal and Coriolis] are > > considered ficticious forces. Could you explain why that difference? > > The fictitious "forces" are pure artifacts of the coordinate system, > while the "real" force is not. Roberts Roberts when your brothers hypnotists trap a long train inside a short tunnel http://www.youtube.com/watch?v=VSRIyDfo_mY&mode=related&search= is the force the train exerts on the doors of the tunnel fictitious or real? If it is fictitious Roberts Roberts, why do your brothers reopen the doors "pretty quickly" as they trap a 80m long pole inside a 40m long barn: http://www.math.ucr.edu/home/baez/physics/Relativity/SR/barn_pole.html "These are the props. You own a barn, 40m long, with automatic doors at either end, that can be opened and closed simultaneously by a switch. You also have a pole, 80m long, which of course won't fit in the barn....So, as the pole passes through the barn, there is an instant when it is completely within the barn. At that instant, you close both doors simultaneously, with your switch. Of course, you open them again pretty quickly, but at least momentarily you had the contracted pole shut up in your barn." Pentcho Valev
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X-Google-Thread: 10f545,fbabe5f5b7edad1e X-Google-Thread: 10b271,a6cbf69709d02d18 X-Google-Thread: fa4c1,a6cbf69709d02d18 X-Google-Thread: f55d3,a6cbf69709d02d18 X-Google-Thread: 1139f8,a6cbf69709d02d18 X-Google-Attributes: gid10f545,gid10b271,gidfa4c1,gidf55d3,gid1139f8,public,usenet X-Google-Language: ENGLISH,ASCII-7-bit Path: arc1-ca.pugleaf.net!g2news2.google.com!postnews.google.com!i38g2000prf.googlegroups.com!not-for-mail From: Pentcho Valev <pvalev@yahoo.com> Newsgroups: sci.physics.relativity,sci.physics,fr.sci.physique,fr.sci.philo,fr.sci.maths Subject: Re: Difference between physics and mathematics Date: 14 Oct 2007 07:01:21 -0700 Organization: http://groups.google.com Lines: 31 Message-ID: <1192345322.420701.14870@i38g2000prf.googlegroups.com> References: <1191952780.146772.75680@d55g2000hsg.googlegroups.com> <F6UOi.7516$H22.3477@news-server.bigpond.net.au> <w5ednTQwhvcGiJDanZ2dnUVZ_gudnZ2d@wavecable.com> <1192042863.070225.122770@y42g2000hsy.googlegroups.com> <1192089567_1469@sicinfo3.epfl.ch> <hImdnRlsq8IgIpPanZ2dnUVZ_judnZ2d@wavecable.com> <1192208919.538514.8780@t8g2000prg.googlegroups.com> <1192269831.408374.318190@t8g2000prg.googlegroups.com> <O4eQi.58375$Um6.20703@newssvr12.news.prodigy.net> NNTP-Posting-Host: 85.91.141.136 Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" X-Trace: posting.google.com 1192370490 24441 127.0.0.1 (14 Oct 2007 14:01:30 GMT) X-Complaints-To: groups-abuse@google.com NNTP-Posting-Date: Sun, 14 Oct 2007 14:01:30 +0000 (UTC) In-Reply-To: <O4eQi.58375$Um6.20703@newssvr12.news.prodigy.net> User-Agent: G2/1.0 X-HTTP-UserAgent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; .NET CLR 1.1.4322; .NET CLR 2.0.50727; .NET CLR 3.0.04506.30),gzip(gfe),gzip(gfe) Complaints-To: groups-abuse@google.com Injection-Info: i38g2000prf.googlegroups.com; posting-host=85.91.141.136; posting-account=ps2QrAMAAAA6_jCuRt2JEIpn5Otqf_w0