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Re: inertial frames of reference

From Sylvia Else <sylvia@not.at.this.address>
Newsgroups sci.physics
Subject Re: inertial frames of reference
Date 2016-01-23 14:43 +1100
Message-ID <dggb7mFd1jpU1@mid.individual.net> (permalink)
References (3 earlier) <n7qpte$ho4$1@gioia.aioe.org> <70edde1c-425a-4192-96e9-795f4481f02d@googlegroups.com> <n7qslt$q4c$1@gioia.aioe.org> <4d84b95f-4d82-4044-8d6c-df367801cdd6@googlegroups.com> <5b7b0578-51f4-4dc5-babb-ab121fbac75a@googlegroups.com>

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On 23/01/2016 2:20 PM, kquirici@yahoo.com wrote:
> On Thursday, January 21, 2016 at 10:48:58 AM UTC-5, kqui...@yahoo.com wrote:
>> On Thursday, January 21, 2016 at 10:15:52 AM UTC-5, Odd Bodkin wrote:
>>> On 1/21/2016 8:57 AM, kquirici@yahoo.com wrote:
>>>> I like that thought experiment. I think of the ball pulling on the string but (usually)
>>>> not the equal and opposite force of the string pulling on the ball. And the notion of
>>>> the missing balancing force that the more general notion of equilibrium leads to. Cool.
>>>
>>> One more comment here because I spotted a mistake that I once made while
>>> learning this subject too -- I guess it's a common mistake.
>>>
>>> It's tempting to say that equilibrium means that the string pulls on the
>>> ball with a force equal to how much the ball is pulling on the string.
>>> But no, that's not what equilibrium means. Equilibrium means that all
>>> the forces on a SINGLE object cancel out. So choose the ball OR the
>>> string, but stick with that one. Now, if you choose the ball, then look
>>> at all the forces acting ON THE BALL and ask if they cancel out. Since
>>> only the string is acting on the ball, there can be no way all the
>>> forces acting on the ball cancel out.
>>>
>>>
>>> --
>>> Odd Bodkin --- maker of fine toys, tools, tables
>>
>> Good ooint. I think I was sort of making that mistake too. One of the virtues of fuzzy and insufficiently worked-out thinking is that one at times only sort of makes mistakes.
>
> So what about this question/suggestion from the first post:
>
> there are no inertial frames of reference because the universe is filled with gravitational fields and hence all objects are accelerating (however slightly).
>
> ?
>

It's not so much the fact that they're accelerating that prevents them 
from being inertial. If you found a volume of space in which the 
gravitational field was constant, and then placed yourself in free fall 
inside the volume, then you would be in an inertial frame even though 
you would be accelerating. However, without looking outside the volume, 
you'd have no way of detecting the fact that you were accelerating. That 
is, you'd find that the laws of physics were the same as for any other 
inertial frame.

In practice, one doesn't find volumes of space like that. However, it's 
easy enough to find volumes in which the field changes very little, and 
the laws of physics in such a place have to be correspondingly close to 
those in a genuinely inertial frame.

Indeed, this is the basis on which general relativity is built.

Sylvia.

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Thread

inertial frames of reference "kquirici@yahoo.com" <kquirici@yahoo.com> - 2016-01-20 11:31 -0800
  Re: inertial frames of reference Sam Wormley <swormley1@gmail.com> - 2016-01-20 13:40 -0600
    Re: inertial frames of reference "reber g=emc^2" <herbertglazier0@gmail.com> - 2016-01-20 13:32 -0800
      Re: inertial frames of reference "kquirici@yahoo.com" <kquirici@yahoo.com> - 2016-01-20 14:14 -0800
    Re: inertial frames of reference jimp@specsol.spam.sux.com - 2016-01-21 05:10 +0000
      Re: inertial frames of reference Sam Wormley <swormley1@gmail.com> - 2016-01-23 10:58 -0600
        Re: inertial frames of reference jimp@specsol.spam.sux.com - 2016-01-23 19:01 +0000
          Re: inertial frames of reference Sam Wormley <swormley1@gmail.com> - 2016-01-23 13:10 -0600
  Re: inertial frames of reference Odd Bodkin <bodkinodd@gmail.com> - 2016-01-20 16:25 -0600
    Re: inertial frames of reference "kquirici@yahoo.com" <kquirici@yahoo.com> - 2016-01-20 19:47 -0800
      Re: inertial frames of reference "kquirici@yahoo.com" <kquirici@yahoo.com> - 2016-01-21 05:37 -0800
      Re: inertial frames of reference Odd Bodkin <bodkinodd@gmail.com> - 2016-01-21 08:28 -0600
        Re: inertial frames of reference "kquirici@yahoo.com" <kquirici@yahoo.com> - 2016-01-21 06:57 -0800
          Re: inertial frames of reference Odd Bodkin <bodkinodd@gmail.com> - 2016-01-21 09:15 -0600
            Re: inertial frames of reference "kquirici@yahoo.com" <kquirici@yahoo.com> - 2016-01-21 07:48 -0800
              Re: inertial frames of reference "kquirici@yahoo.com" <kquirici@yahoo.com> - 2016-01-22 19:20 -0800
                Re: inertial frames of reference Sylvia Else <sylvia@not.at.this.address> - 2016-01-23 14:43 +1100
                Re: inertial frames of reference Odd Bodkin <bodkinodd@gmail.com> - 2016-01-23 12:11 -0600
                Re: inertial frames of reference "kquirici@yahoo.com" <kquirici@yahoo.com> - 2016-01-23 13:15 -0800
                Re: inertial frames of reference "kquirici@yahoo.com" <kquirici@yahoo.com> - 2016-01-24 04:48 -0800
                Re: inertial frames of reference HVAC <mr.hvac@gmail.com> - 2016-01-24 08:33 -0800
                Re: inertial frames of reference benj <none@gmail.com> - 2016-01-25 01:57 -0500
                Re: inertial frames of reference jay moseley <jaymoseley@hotmail.com> - 2016-01-25 05:32 -0800
                Re: inertial frames of reference Odd Bodkin <bodkinodd@gmail.com> - 2016-01-25 10:56 -0600
                Re: inertial frames of reference HVAC <mr.hvac@gmail.com> - 2016-01-26 06:34 -0800
                Re: inertial frames of reference benj <none@gmail.com> - 2016-01-26 14:13 -0500
                Re: inertial frames of reference HVAC <mr.hvac@gmail.com> - 2016-01-24 08:33 -0800
                Re: inertial frames of reference benj <none@gmail.com> - 2016-01-25 01:58 -0500
                Re: inertial frames of reference Odd Bodkin <bodkinodd@gmail.com> - 2016-01-25 10:09 -0600
                Re: inertial frames of reference "kquirici@yahoo.com" <kquirici@yahoo.com> - 2016-01-25 09:56 -0800
                Re: inertial frames of reference Odd Bodkin <bodkinodd@gmail.com> - 2016-01-25 13:29 -0600
                Re: inertial frames of reference Odd Bodkin <bodkinodd@gmail.com> - 2016-01-25 09:25 -0600
                Re: inertial frames of reference "kquirici@yahoo.com" <kquirici@yahoo.com> - 2016-01-25 09:48 -0800
                Re: inertial frames of reference Odd Bodkin <bodkinodd@gmail.com> - 2016-01-25 11:55 -0600
                Re: inertial frames of reference "kquirici@yahoo.com" <kquirici@yahoo.com> - 2016-01-25 14:57 -0800
        Re: inertial frames of reference jay moseley <jaymoseley@hotmail.com> - 2016-01-24 16:03 -0800
          Re: inertial frames of reference Sam Wormley <swormley1@gmail.com> - 2016-01-24 18:32 -0600
            Re: inertial frames of reference jay moseley <jaymoseley@hotmail.com> - 2016-01-25 00:50 -0800
              Re: inertial frames of reference Odd Bodkin <bodkinodd@gmail.com> - 2016-01-25 10:52 -0600
                Re: inertial frames of reference jay moseley <jaymoseley@hotmail.com> - 2016-01-25 11:20 -0800
                Re: inertial frames of reference Odd Bodkin <bodkinodd@gmail.com> - 2016-01-25 13:34 -0600
                Re: inertial frames of reference jay moseley <jaymoseley@hotmail.com> - 2016-01-25 15:41 -0800
                Re: inertial frames of reference Odd Bodkin <bodkinodd@gmail.com> - 2016-01-26 07:25 -0600
                Re: inertial frames of reference jay moseley <jaymoseley@hotmail.com> - 2016-01-26 10:54 -0800
                Re: inertial frames of reference Odd Bodkin <bodkinodd@gmail.com> - 2016-01-26 15:32 -0600
                Re: inertial frames of reference jay moseley <jaymoseley@hotmail.com> - 2016-01-27 03:15 -0800
                Re: inertial frames of reference Odd Bodkin <bodkinodd@gmail.com> - 2016-01-27 10:18 -0600
                Re: inertial frames of reference jay moseley <jaymoseley@hotmail.com> - 2016-01-27 12:52 -0800
                Re: inertial frames of reference Odd Bodkin <bodkinodd@gmail.com> - 2016-01-27 15:51 -0600
                Re: inertial frames of reference jay moseley <jaymoseley@hotmail.com> - 2016-01-27 14:09 -0800
                Re: inertial frames of reference Odd Bodkin <bodkinodd@gmail.com> - 2016-01-27 16:23 -0600
                Re: inertial frames of reference jay moseley <jaymoseley@hotmail.com> - 2016-01-28 05:26 -0800
                Re: inertial frames of reference Odd Bodkin <bodkinodd@gmail.com> - 2016-01-28 09:10 -0600
                Re: inertial frames of reference jay moseley <jaymoseley@hotmail.com> - 2016-01-28 10:01 -0800
                Re: inertial frames of reference Odd Bodkin <bodkinodd@gmail.com> - 2016-01-28 13:14 -0600
                Re: inertial frames of reference jay moseley <jaymoseley@hotmail.com> - 2016-01-28 13:02 -0800
                Re: inertial frames of reference Odd Bodkin <bodkinodd@gmail.com> - 2016-01-28 16:30 -0600
                Re: inertial frames of reference jay moseley <jaymoseley@hotmail.com> - 2016-01-28 15:06 -0800
                Re: inertial frames of reference Odd Bodkin <bodkinodd@gmail.com> - 2016-01-28 17:15 -0600
                Re: inertial frames of reference "kquirici@yahoo.com" <kquirici@yahoo.com> - 2016-01-28 18:00 -0800
                Re: inertial frames of reference "kquirici@yahoo.com" <kquirici@yahoo.com> - 2016-01-29 04:47 -0800
                Re: inertial frames of reference Odd Bodkin <bodkinodd@gmail.com> - 2016-01-29 08:19 -0600
                Re: inertial frames of reference Odd Bodkin <bodkinodd@gmail.com> - 2016-01-29 07:54 -0600
                Re: inertial frames of reference "kquirici@yahoo.com" <kquirici@yahoo.com> - 2016-01-29 06:44 -0800
                Re: inertial frames of reference Sam Wormley <swormley1@gmail.com> - 2016-01-29 08:53 -0600
                Re: inertial frames of reference HVAC <mr.hvac@gmail.com> - 2016-01-29 07:07 -0800
                Re: inertial frames of reference "kquirici@yahoo.com" <kquirici@yahoo.com> - 2016-01-29 07:24 -0800
                Re: inertial frames of reference "kquirici@yahoo.com" <kquirici@yahoo.com> - 2016-01-29 07:45 -0800
                Re: inertial frames of reference Odd Bodkin <bodkinodd@gmail.com> - 2016-01-29 10:32 -0600
                Re: inertial frames of reference HVAC <mr.hvac@gmail.com> - 2016-01-29 08:50 -0800
                Re: inertial frames of reference benj <none@gmail.com> - 2016-01-29 12:50 -0500
                Re: Ben Jacoby hates the truth because it convicts him. benj <none@gmail.com> - 2016-01-29 14:01 -0500
                Re: inertial frames of reference Odd Bodkin <bodkinodd@gmail.com> - 2016-01-29 13:27 -0600
                Re: inertial frames of reference Odd Bodkin <bodkinodd@gmail.com> - 2016-01-29 10:52 -0600
                Re: inertial frames of reference "kquirici@yahoo.com" <kquirici@yahoo.com> - 2016-01-29 09:33 -0800
                Re: inertial frames of reference Odd Bodkin <bodkinodd@gmail.com> - 2016-01-29 12:11 -0600
                Re: inertial frames of reference benj <none@gmail.com> - 2016-01-29 12:59 -0500
                Re: inertial frames of reference Odd Bodkin <bodkinodd@gmail.com> - 2016-01-29 10:08 -0600
                Re: inertial frames of reference benj <none@gmail.com> - 2016-01-29 12:39 -0500
                Re: inertial frames of reference Odd Bodkin <bodkinodd@gmail.com> - 2016-01-29 12:16 -0600
                Re: inertial frames of reference benj <none@gmail.com> - 2016-01-29 14:06 -0500
                Re: inertial frames of reference Odd Bodkin <bodkinodd@gmail.com> - 2016-01-29 14:40 -0600
                Re: inertial frames of reference HVAC <mr.hvac@gmail.com> - 2016-01-29 04:56 -0800
                Re: inertial frames of reference HVAC <mr.hvac@gmail.com> - 2016-01-29 04:56 -0800
                Re: inertial frames of reference "kquirici@yahoo.com" <kquirici@yahoo.com> - 2016-01-27 17:56 -0800
                Re: inertial frames of reference "kquirici@yahoo.com" <kquirici@yahoo.com> - 2016-01-27 18:57 -0800
                Re: inertial frames of reference jay moseley <jaymoseley@hotmail.com> - 2016-01-28 05:43 -0800
                Re: inertial frames of reference Odd Bodkin <bodkinodd@gmail.com> - 2016-01-28 09:13 -0600
                Re: inertial frames of reference Odd Bodkin <bodkinodd@gmail.com> - 2016-01-28 09:19 -0600
                Re: inertial frames of reference jay moseley <jaymoseley@hotmail.com> - 2016-01-28 14:47 -0800
                Re: inertial frames of reference Sam Wormley <swormley1@gmail.com> - 2016-01-28 16:52 -0600
                Re: inertial frames of reference Odd Bodkin <bodkinodd@gmail.com> - 2016-01-28 17:10 -0600
                Re: inertial frames of reference jay moseley <jaymoseley@hotmail.com> - 2016-01-29 01:13 -0800
                Re: inertial frames of reference Odd Bodkin <bodkinodd@gmail.com> - 2016-01-29 08:16 -0600
                Re: inertial frames of reference jay moseley <jaymoseley@hotmail.com> - 2016-01-29 09:26 -0800
                Re: inertial frames of reference Odd Bodkin <bodkinodd@gmail.com> - 2016-01-29 12:05 -0600
                Re: inertial frames of reference jay moseley <jaymoseley@hotmail.com> - 2016-01-29 10:52 -0800
                Re: inertial frames of reference Odd Bodkin <bodkinodd@gmail.com> - 2016-01-29 14:31 -0600
                Re: inertial frames of reference jay moseley <jaymoseley@hotmail.com> - 2016-01-30 07:37 -0800
                Re: inertial frames of reference Odd Bodkin <bodkinodd@gmail.com> - 2016-01-31 13:58 -0600
                Re: inertial frames of reference jay moseley <jaymoseley@hotmail.com> - 2016-02-01 03:05 -0800
                Re: inertial frames of reference Odd Bodkin <bodkinodd@gmail.com> - 2016-02-01 09:40 -0600
                Re: inertial frames of reference jay moseley <jaymoseley@hotmail.com> - 2016-01-29 09:34 -0800
                Re: inertial frames of reference Odd Bodkin <bodkinodd@gmail.com> - 2016-01-29 12:14 -0600
                Re: inertial frames of reference jay moseley <jaymoseley@hotmail.com> - 2016-01-29 10:58 -0800
                Re: inertial frames of reference Odd Bodkin <bodkinodd@gmail.com> - 2016-01-29 14:39 -0600
                Re: inertial frames of reference jay moseley <jaymoseley@hotmail.com> - 2016-01-30 07:43 -0800
                Re: inertial frames of reference Odd Bodkin <bodkinodd@gmail.com> - 2016-01-31 14:01 -0600
                Re: inertial frames of reference benj <none@gmail.com> - 2016-01-29 14:12 -0500
                Re: inertial frames of reference Odd Bodkin <bodkinodd@gmail.com> - 2016-01-28 08:59 -0600
                Re: inertial frames of reference "kquirici@yahoo.com" <kquirici@yahoo.com> - 2016-01-28 09:03 -0800
                Re: inertial frames of reference Odd Bodkin <bodkinodd@gmail.com> - 2016-01-28 11:40 -0600
                Re: inertial frames of reference kenseto <setoken@att.net> - 2016-01-30 11:36 -0800
          Re: inertial frames of reference Odd Bodkin <bodkinodd@gmail.com> - 2016-01-25 10:44 -0600
  Re: inertial frames of reference "kquirici@yahoo.com" <kquirici@yahoo.com> - 2016-01-23 05:19 -0800
    Re: inertial frames of reference "kquirici@yahoo.com" <kquirici@yahoo.com> - 2016-01-23 06:10 -0800
  Re: inertial frames of reference "kquirici@yahoo.com" <kquirici@yahoo.com> - 2016-01-29 10:06 -0800
  Re: inertial frames of reference "kquirici@yahoo.com" <kquirici@yahoo.com> - 2016-01-31 07:23 -0800
    Re: inertial frames of reference jay moseley <jaymoseley@hotmail.com> - 2016-01-31 08:53 -0800
      Re: inertial frames of reference "kquirici@yahoo.com" <kquirici@yahoo.com> - 2016-01-31 11:54 -0800
        Re: inertial frames of reference Odd Bodkin <bodkinodd@gmail.com> - 2016-01-31 14:04 -0600
          Re: inertial frames of reference xxein1@att.net - 2016-01-31 15:01 -0800
            Re: inertial frames of reference Odd Bodkin <bodkinodd@gmail.com> - 2016-01-31 19:07 -0600
      Re: inertial frames of reference Odd Bodkin <bodkinodd@gmail.com> - 2016-01-31 13:54 -0600
        Re: inertial frames of reference "kquirici@yahoo.com" <kquirici@yahoo.com> - 2016-01-31 15:04 -0800
          Re: inertial frames of reference jay moseley <jaymoseley@hotmail.com> - 2016-02-01 03:37 -0800
            Re: inertial frames of reference "kquirici@yahoo.com" <kquirici@yahoo.com> - 2016-02-01 04:18 -0800
              Re: inertial frames of reference "kquirici@yahoo.com" <kquirici@yahoo.com> - 2016-02-01 04:26 -0800
              Re: inertial frames of reference Odd Bodkin <bodkinodd@gmail.com> - 2016-02-01 09:52 -0600
                Re: inertial frames of reference "kquirici@yahoo.com" <kquirici@yahoo.com> - 2016-02-01 08:34 -0800
                Re: inertial frames of reference jay moseley <jaymoseley@hotmail.com> - 2016-02-01 10:40 -0800
                Re: inertial frames of reference Odd Bodkin <bodkinodd@gmail.com> - 2016-02-01 12:55 -0600
                Re: inertial frames of reference Odd Bodkin <bodkinodd@gmail.com> - 2016-02-01 13:55 -0600
                Re: inertial frames of reference jay moseley <jaymoseley@hotmail.com> - 2016-02-01 16:38 -0800
                Re: inertial frames of reference Odd Bodkin <bodkinodd@gmail.com> - 2016-02-02 07:19 -0600
                Re: inertial frames of reference jay moseley <jaymoseley@hotmail.com> - 2016-02-02 09:53 -0800
                Re: inertial frames of reference Odd Bodkin <bodkinodd@gmail.com> - 2016-02-02 12:55 -0600
                Re: inertial frames of reference "kquirici@yahoo.com" <kquirici@yahoo.com> - 2016-02-01 16:27 -0800
                Re: inertial frames of reference jay moseley <jaymoseley@hotmail.com> - 2016-02-02 01:39 -0800
                Re: inertial frames of reference "kquirici@yahoo.com" <kquirici@yahoo.com> - 2016-02-02 05:49 -0800
                Re: inertial frames of reference jay moseley <jaymoseley@hotmail.com> - 2016-02-02 10:49 -0800
                Re: inertial frames of reference Odd Bodkin <bodkinodd@gmail.com> - 2016-02-02 13:20 -0600
                Re: inertial frames of reference Odd Bodkin <bodkinodd@gmail.com> - 2016-02-02 09:43 -0600
            Re: inertial frames of reference "kquirici@yahoo.com" <kquirici@yahoo.com> - 2016-02-01 04:20 -0800
              Re: inertial frames of reference Odd Bodkin <bodkinodd@gmail.com> - 2016-02-01 09:55 -0600
            Re: inertial frames of reference Odd Bodkin <bodkinodd@gmail.com> - 2016-02-01 09:43 -0600
    Re: inertial frames of reference Odd Bodkin <bodkinodd@gmail.com> - 2016-01-31 13:51 -0600

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