From: tjroberts137@sbcglobal.net   
      
   On 7/1/18 2:52 PM, Ed Lake wrote:   
   > On Sunday, July 1, 2018 at 10:29:01 AM UTC-5, Tom Roberts wrote:   
   >> On 6/29/18 5:32 PM, Ed Lake wrote:   
   >>> If the moving observer drops a stone and sees it fall straight down,   
   >>> while a stationary observer sees that stone fall in a parabolic curve,   
   >>> their conflicting views cannot both be "correct."   
   >>   
   >> This is simply not true. Both observers observe what they observe. Both   
   >> MUST be correct.   
   >   
   > Another baseless argument.   
      
   No, it is not "baseless" at all -- that is what those words mean.   
      
   Have you never been on a train and dropped something while it is en route? --   
   if   
   not, go find a train and do it (or use a car).   
      
   It is QUITE CLEAR that a dropped object on a train falls straight down RELATIVE   
   TO THE TRAIN [#]. And it is also QUITE CLEAR that the same object falls in a   
   parabolic arc RELATIVE TO THE EMBANKMENT. BOTH observations are correct,   
   because   
   that is what those observers actually observe.   
      
   NOTE: I reject and ignore your outrageous attempt to redefine the word   
   "correct". Instead, I will write out your meaning, "consistent with the laws   
   of physics". Such egregious redefinitions only serve to obscure the argument   
   and   
   confuse the participants.   
      
   	[#] Here the context is Newtonian physics, and I ignore   
   	the distance the train travels during the fall compared   
   	to the radius of the earth. That is, here gravity points   
   	straight down, even though on earth it actually changes   
   	direction slightly as the train moves. I do this to   
   	avoid getting bogged down in irrelevant minutiae. Note   
   	that a more careful analysis that includes this does NOT   
   	change the basic conclusion.   
      
   > Observers observe what they observe, but that doesn't automatically make   
   > anything "correct."   
      
   Sure it does, because that is what those words mean. Both observer's   
   observations are also consistent with the laws of physics. After all, no   
   observer or physical phenomenon can possibly violate those laws.   
      
   You claim that the train observer's observation is not consistent with the laws   
   of physics -- how do you suppose that the train observer or the stone can   
   violate those laws?????   
      
   	Hint: If it is possible to violate them, then they aren't   
   	really "laws of physics".   
      
   > So, the observation that the stone traveled in a parabolic arc is the   
   > "correct" observation.   
      
   Sure, RELATIVE TO THE EMBANKMENT. But it is not the only correct observation --   
   the observation of the train observer is also correct. Both are also consistent   
   with the laws of physics.   
      
   > Within two closed inertial frames of reference *experiments* work   
   > identically. HOWEVER, when one frame of reference is observed from another   
   > frame of reference, the experiments may not work identically.   
      
   This is nonsense. You do not understand what frames of reference actually are.   
      
   A frame of reference is a set of coordinates relative to which an experiment   
   can   
   be DESCRIBED. The frame is PURELY IN THE MIND OF THE ANALYST, and used FOR   
   DESCRIPTION ONLY; nature does not use frames in any way. So whichever frame is   
   used by the analyst/observer, that choice cannot possibly affect the results of   
   the experiment (here the trajectory of the falling stone).   
      
   The trajectory of the stone before it is dropped is important to how the laws   
   of   
   physics determine its trajectory after it is dropped. But the fact that it is   
   initially at rest in the train frame is IRRELEVANT to those laws [@], and to   
   the   
   its subsequent trajectory. But being initially at rest in the train frame is   
   important to the DESCRIPTION of the stone's trajectory relative to the train   
   frame. Similarly, the initial forward motion of the stone relative to the   
   embankment frame is IRRELEVANT to those laws [@], and to its subsequent   
   trajectory, but is important to the DESCRIPTION of the stone's trajectory   
   relative to the embankment frame.   
      
   	[@] Because the laws of physics are INDEPENDENT of frame;   
   	nature does not use frames in any way.   
      
   IOW: the dropped stone moves in a fashion determined by the laws of physics.   
   Those laws can be described in ANY frame of reference, and necessarily must   
   give   
   THE SAME trajectory of the stone -- after all there is only one stone and it is   
   dropped only once, so it can have only one trajectory. If the laws are   
   accurate,   
   they MUST predict this one trajectory, and must do so using ANY frame of   
   reference.   
      
   The train observer describes the stone as falling straight down, and the   
   embankment observer describes it as falling in a parabolic arc. BOTH   
   descriptions are correct (in that they accurately describe what is observed by   
   each observer), BOTH descriptions describe the ONE trajectory of the stone   
   (from   
   different perspectives using different frames), and BOTH descriptions are   
   consistent with the laws of physics.   
      
   > The same laws are valid in EVERY inertial frame, but they can produce   
   > different results if one frame is moving relative to the other.   
      
   Hmmmm. The laws of physics are INDEPENDENT of frame, and they yield a result   
   that is INDEPENDENT of frame (I use the normal meaning of "result"). But the   
   DESCRIPTIONS of the result using different frames can certainly be different.   
      
   If by "result" you mean the normal "what actually happened", then your   
   statement   
   here is just plain wrong; if by "result" you intend the unusual meaning   
   "DESCRIPTION of what actually happened", then of course different frames can   
   yield different descriptions.   
      
   	[Do not expect me to continue. You clearly do not understand   
   	 very basic concepts of physics, or even basic English usage.   
   	 It is useless to try to continue until you learn the basics.]   
      
   Tom Roberts   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)