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From: artful on 6 Aug 2010 23:14 On Aug 7, 10:56 am, glird <gl...(a)aol.com> wrote: > On Aug 6, 7:21 pm, Tom Roberts wrote: > > > glird wrote: > > >>< Given that the equation e = mc^2 (energy equals mass times {the speed of light in vacuo} squared) has been experimentally verified, explain how the quantity of energy can vary if the m and c do not.> > > >< You do not understand what E=mc^2 means. It means the REST ENERGY of an object is proportional to its mass. For moving objects, their mass remains fixed but their energy is increased. > > > You're talking about the wrong equation, Tom. No .. hes not > The ones you refer to seem to be > Longitudinal mass = m/q, > Transverse mass = m/Q, I'm well aware of them. That is not what Tom was talking about. He is talking about proper/rest/invariant mass. Not the two frame- dependent masses. > in which Q = q^2 = c^2 - v^2, mass is the weight-is-a-form-of-energy > of moving objects, and m is your "REST ENERGY" of a body, i.e. its > energy when at rest on Earth. It has nothing to do with earth.
From: harald on 7 Aug 2010 05:18 On Aug 6, 8:17 pm, PD <thedraperfam...(a)gmail.com> wrote: > On Aug 6, 1:02 pm, Da Do Ron Ron <ron_ai...(a)hotmail.com> wrote: > > > Harald generously listed *two* allegedly supporting experiments: > > > > - exact deflection of electron beams (Lorentz 1904, Einstein 1905). > > > - the effect of speed on clocks (Einstein 1905; applied in the GPS > > > system). > > > I will simply ignore the first because it is not even listed here:http://www.xs4all.nl/~johanw/PhysFAQ/Relativity/SR/experiments.html > > Why would you do that? > Predictions come in two sorts -- that which can be tested in a > targeted experiment, and that which is essential to the design of a > device or a process (e.g. a practical application). He listed two of > the latter. Actually, the electron experiment was the most important targeted experiment in the early days - not surprising with such titles as "Electrodynamics of moving bodies". Here's another link: http://en.wikipedia.org/wiki/History_of_special_relativity#Kaufmann-Bucherer_experiments Harald > You cited a partial compendium of the former. > The point is, relativity is so established that it is routinely used > in everyday applications. If relativity did not make reliable > predictions, these applications would work at best by accident. > > > > > As for the second, can Harald define "speed"? (Is it a relative speed > > or an absolute speed?) > > I'm not Harald, but I'm sure you've been told that as far as we know, > all speeds are relative, and that's the context of the prediction.
From: Tom Roberts on 7 Aug 2010 11:47 GogoJF wrote: > On Aug 5, 2:31 pm, Tom Roberts <tjroberts...(a)sbcglobal.net> wrote: >> Nature uses no observers, so valid models of physics must not use observers, or >> at least be independent of observer. > > So, you say that all our models should be devoid of the > observer, in order to measure nature correctly- that we should, > instead, use our devices which are more precise and accurate? Hmmm. You can read what I said above. That's what I said. This is not about precision or accuracy, it is about faithfully modeling nature. Our models must, of course, include measuring devices, and must model the measurement process. For instance, in GR to model the length that a ruler measures, one integrates the metric along the spacelike path of the ruler. To model the time interval displayed on a clock, one integrates the metric along the clock's timelike path. > At the > same time, this statement disqualifies all observational measure. No. It merely points out that the observer is not part of the model. Measurements are included in the model. > Einstein's description of relativity routinely uses the observer in > the thought experiment. Sure. But you must understand what his observers did -- they applied measurement instruments, nothing more. So modeling those instruments is sufficient. This was the literary style of his day, and it persists to today, but there is no need for a human observer, or any other kind of observer; modeling the instruments is sufficient. This is not true for the Copenhagen interpretation of quantum mechanics. That IMHO is a fatal flaw. Tom Roberts
From: spudnik on 7 Aug 2010 15:47 that's in its own "resting" frame of reference, as with Galilean relativity. I also appreciate the citation of Huyghens, whhofrom ____ got the math to make the inverse- second-power law from Kepler's orbital constraints. all of these things are "invariant" within the object's frame of rest, so, you can just say that the relativistic increase of mass etc., is just a matter of trying to stop it. of ocurse, Minkowski obfuscated every God-am thing with his little lectures about phase-space; then, he ... nevermind! > It has nothing to do with earth. thus: you were around, what -- a FOX news transmitter?... well, you'd get more radiation, sitting so close to TV!... so, anyway, check the UNSCEAR 2000 report; if it had been redacted of the word, Chernobyl, you wouldn't know that it was the same hyped-over area. yes, the SU authorities mistakenly tried to cover it up, such as they could for a while, and thus also failed to distrbute the iodine tablet prophylactics for the possiblity of Cesium-137 poisoning, but that is mostly ameliorated by not drinking milk from grass-fed cows, for a number of months. > Bullshit. Unlike you, I was around at the time. The west didn't even know > something was happening until they detected radioactive elements in the wind > coming over europe. One of the complaints was that the soviets didn't let > the world know that chernobyl had melted down. The evacuation was because > people were dying from massive radiation poisoning. thus: ah, yes; resistanceless!... so, for realism, what'd be the minimum "boost," as the bobsledder approacheth the antipode at sealevel, to get back to the start? I didn't think, though, that the brachistochrone/tautochrone was cycloidal, but that roundtrip makes me wonder. > > just drop it. > Well, well that's just a trivial case ;-) How about a half-pipe > brachistochrone going from point A 5000km above the ground to > ground-zero at the antipodal point and ending at point A again going > once around the equator? --les ducs d'oil! http://tarpley.net --Light, A History! http://wlym.com
From: GogoJF on 9 Aug 2010 19:45
On Aug 7, 10:47 am, Tom Roberts <tjroberts...(a)sbcglobal.net> wrote: > GogoJF wrote: > > On Aug 5, 2:31 pm, Tom Roberts <tjroberts...(a)sbcglobal.net> wrote: > >> Nature uses no observers, so valid models of physics must not use observers, or > >> at least be independent of observer. > > > So, you say that all our models should be devoid of the > > observer, in order to measure nature correctly- that we should, > > instead, use our devices which are more precise and accurate? > > Hmmm. You can read what I said above. That's what I said. This is not about > precision or accuracy, it is about faithfully modeling nature. > > Our models must, of course, include measuring devices, and must model the > measurement process. > > For instance, in GR to model the length that a ruler measures, > one integrates the metric along the spacelike path of the ruler. > To model the time interval displayed on a clock, one integrates > the metric along the clock's timelike path. > > > At the > > same time, this statement disqualifies all observational measure. > > No. It merely points out that the observer is not part of the model. > Measurements are included in the model. > > > Einstein's description of relativity routinely uses the observer in > > the thought experiment. > > Sure. But you must understand what his observers did -- they applied measurement > instruments, nothing more. So modeling those instruments is sufficient. This was > the literary style of his day, and it persists to today, but there is no need > for a human observer, or any other kind of observer; modeling the instruments is > sufficient. > > This is not true for the Copenhagen interpretation of quantum > mechanics. That IMHO is a fatal flaw. > > Tom Roberts In this situation, one must ask oneself, what are we ultimately trying to accomplish- a great understanding or a great invention of the situation? Often one comes with the other. But, if I had to pick one, I think it would be the invention- because understanding takes years and years- and the invention just makes our lives easier. |