According to 1905 Relativity, a single material point must be always at rest
in [Relativity]
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From: eric gisse on 20 May 2010 13:54 valls(a)icmf.inf.cu wrote: > In his first Relativity paper (30June1905), after declaring the ether > superfluous, Einstein considers a material point at rest. He uses a > system of Cartesian coordinates in which the equations of Newtonian > mechanics and Euclidean geometry hold good. If the massive body is > alone (and then without a Newtonian gravitational force acting on it), > it must remains forever at rest in its own centre of mass inertial > frame. > RVHG (Rafael Valls Hidalgo-Gato) Idiotic thread alert.
From: PD on 20 May 2010 14:09 On May 20, 8:19 am, va...(a)icmf.inf.cu wrote: > In his first Relativity paper (30June1905), after declaring the ether > superfluous, Einstein considers a material point at rest. He uses a > system of Cartesian coordinates in which the equations of Newtonian > mechanics and Euclidean geometry hold good. If the massive body is > alone (and then without a Newtonian gravitational force acting on it), > it must remains forever at rest in its own centre of mass inertial > frame. Yes. So? Every object lives in an infinite multitude of frames. The ones that have constant velocity with the frame you just described, plus this frame itself, constitutes the set of inertial frames. The question of interest is what is the relationship between various physical properties, as measured in different inertial frames?
From: valls on 20 May 2010 15:26 On 20 mayo, 11:32, Darwin123 <drosen0...(a)yahoo.com> wrote: > On May 20, 9:19 am, va...(a)icmf.inf.cu wrote: > > > In his first Relativity paper (30June1905), after declaring the ether > > superfluous, Einstein considers a material point at rest. He uses a > > system of Cartesian coordinates in which the equations of Newtonian > > mechanics and Euclidean geometry hold good. If the massive body is > > alone (and then without a Newtonian gravitational force acting on it), > > it must remains forever at rest in its own centre of mass inertial > > frame. > > RVHG (Rafael Valls Hidalgo-Gato) > > Yes it does. So? Conservation of momentum applies in both Galilean and > Lorentz invariant systems. > "An object at rest tends to stay at rest unless acted on by some > external force." That is Newton's first law. It is good in any > inertial frame. We are in total agreement (at least here, see my answer to your other post in this thread). RVHG (Rafael Valls Hidalgo-Gato)
From: Androcles on 20 May 2010 16:01 "Darwin123" <drosen0000(a)yahoo.com> wrote in message news:f38863b7-579b-4bd0-aaa1-11016a68ce14(a)o15g2000vbb.googlegroups.com... On May 20, 12:28 pm, va...(a)icmf.inf.cu wrote: > On 20 mayo, 08:50, harald <h...(a)swissonline.ch> wrote:> On May 20, 3:19 > pm, va...(a)icmf.inf.cu wrote: At the > end of paragraph 4 in the referred 1905 Einsteins paper, you can find > already the ECI (the rotating Earth with a centre of mass at rest) > with the moving system (clock at the equator) forming part of it. > Ahh, now I see what you are driving at. Einstein is referring to the ECI as an inertial frame, when it is obviously not an inertial frame. The center of the earth orbits the sun, and the sun orbits the center of the Milky Way. Einstein is analyzing an experiment on the surface of the earth, considering only the centripetal acceleration of the earth's surface. The contributions of the earth's orbit around the sun, and the suns orbit around our galaxy, is not considered. I don't think ============================================== We all know that, why advertise it?
From: harald on 20 May 2010 17:43
On May 20, 4:28 pm, va...(a)icmf.inf.cu wrote: > On 20 mayo, 08:50, harald <h...(a)swissonline.ch> wrote:> On May 20, 3:19 pm, va...(a)icmf.inf.cu wrote: > > > > In his first Relativity paper (30June1905), after declaring the ether > > > superfluous, Einstein considers a material point at rest. He uses a > > > system of Cartesian coordinates in which the equations of Newtonian > > > mechanics and Euclidean geometry hold good. If the massive body is > > > alone (and then without a Newtonian gravitational force acting on it), > > > it must remains forever at rest in its own centre of mass inertial > > > frame. > > > RVHG (Rafael Valls Hidalgo-Gato) > > > If it were alone, yes. But then a theory about relative motion of > > reference systems would certainly be superfluous. ;-) > > But who says that the material point must be always alone? Consider > the Solar System centre of mass inertial reference frame (SS) and the > GPS ECI one. The last can be modelled as a material point that is not > alone (is part of the SS one). As a huge experimental evidence put out > of any doubt, you can model the SS as a single material point at rest, > describing later the Earth (ECI) movement in the SS without any > problem at all. In a similar way, all GPS satellite movements > (including the ground clock ones) can be described in an ECI modelled > as a single material point at rest. Good / so now you do consider a not so alone particle, and even not a point if you want to establish time measurements at different places. > Do you consider yet superfluous a theory about relative motion of > reference systems? Note that the moving system must be always part > of the stationary system, and a stationary system moving with > respect to a moving system at rest is nothing more that a huge > absurd (do you remember Ptolomys Sun going around the Earth?). Following your arguments elsewhere, here we dont care about what you think. Einsteins thoery does not prefer one inertial system over the other, it is not supporting your theory. Regards, Harald > At the > end of paragraph 4 in the referred 1905 Einsteins paper, you can find > already the ECI (the rotating Earth with a centre of mass at rest) > with the moving system (clock at the equator) forming part of it. > > > Cheers, > > Harald > > RVHG (Rafael Valls Hidalgo-Gato) |