Re: Hobba's misconceptions
- From: surrealistic-dream@xxxxxxxxxxx
- Date: 10 Dec 2005 06:04:32 -0800
Bill Hobba wrote:
> "Mike" <eleatis@xxxxxxxx> wrote in message
> news:1134214183.192472.326840@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
> >
> > Bill Hobba wrote:
> >
> > [snip apologetic crap]
> >
> >>
> >> That experiment shows no such thing. See Tom Roberts excellent analysis:
> >> http://groups.google.com/group/sci.physics.relativity/msg/d157eb4b0462c947?dmode=source
> >
> >
> > Next thing we know, you are out in the street screaming "Roberts for
> > President". For how long are you going to hide your misconceptions
> > behind someone elses's back?
>
> How about addressing the content of the post rather than your usual silly
> verbal diarrhea?
>
> >
> >
> >>
> >> > Hobba does
> >> > not understand that when curvilinear motion comes into play, his silly
> >> > argument breaks down. Consider the following REAL experiment, not the
> >> > type of though experiments he has been brainwashed with:
> >> >
> >> > On a rotaing disk there is a spring attached to its center and a steel
> >> > ball attached to its other end, resting on the disk. When we start
> >> > rotate the disk uniformly, the spring extends by a small distance
> >> > delat(x). The ball now is at rest in its own frame of reference.
> >>
> >> Any object is at rest in some frame. In this case it is non inertial,
> >> and
> >> is subject to forces of acceleration.
> >
> > Your statement went further than the first law.
> >
>
> It is a simple application of F=MA.
>
> > You said in Newtonian
> > Mechanics there is no such thing as a preferred reference frame.
> >
>
> That is not what I said - I said there was no such thing as an absolute
> frame - meaning a (as in one) frame where the laws of physics are different.
> Frames can be preferred because they simplify the problem.
>
> But actually even though I replied one of my favouyrite movies the Johlson
> Story is about to start. It is much more important than responding to your
> rubbish.
Bill, Mike is partly correct, at least insofsar as his comments about
Newton's invention of an absolute space in which accelerations live. It
was this space (or better conceived of as, not a single space, but as
any inertial state of motion) which so bothered Mach and then Einstein.
I don't recall ever reading that Newton's so-called absolute
acceleration space was ever taken as Lorentz's rest space of the
luminiferous ether, but some people may have done that. Though,
logically we have no imperative to equate them.
Rare is the mechanics book of the last century that even mentions
Newton's absolute acceleration space.
The following quotes are from Einstein's book of essays, Ideas and
Opinions:
<BEGIN QUOTE>
There is yet another factor underlying the evolution of the general
theory of relativity. As Ernst Mach insistently pointed out, the
Newtonian theory is unsatisfactory in the following respect: if one
considers motion from the purely descriptive, not from the causal,
point of view, it only exists as relative motion of things with respect
to one another. But the acceleration which figures in Newton's
equations of motion is unintelligible if one starts with the concept of
relative motion. It compelled Newton to invent a physical space in
relation to which acceleration was supposed to exist. This introduction
ad hoc of the concept of absolute space, while logically
unexceptionable, nevertheless seems unsatisfactory. Hence Mach's
attempt to alter the mechanical equations in such away that the inertia
of bodies is traced back to relative motion on their part not as
against absolute space but as against the totality of other ponderable
bodies. In the state of knowledge then existing, his attempt was bound
to fail.
<END QUOTE>
--- On the Theory of Relativity, p. 248
<BEGIN QUOTE>
In so far as geometry is conceived as the science of laws governing the
mutual spatial relations of practically rigid bodies, it is to be
regarded as the oldest branch of physics. This science was able, as I
have already observed, to get along without the concept of space as
such, the ideal corporeal forms---point, straight line, plane,
segment---being sufficient for its needs. On the other hand, space as a
whole, as conceived by Descartes, was absolutely necessary to Newtonian
physics. For dynamics cannot manage with the concepts of the mass point
and the (temporally variable) distance between mass points alone. In
Newton's equations of motion, the concept of acceleration plays a
fundamental part, which cannot be defined by the temporally variable
intervals between points alone. Newton's acceleration is only
conceivable or definable in relation to space as a whole. Thus to the
geometrical reality of the concept of space anew inertia-determining
function of space was added. When Newton described space as absolute,
he no doubt meant this real significance of space, which made it
necessary for him to attribute to it a quite definite state of motion,
which yet did not appear to be fully determined by the phenomena of
mechanics. This space was conceived as absolute in another sense also;
its inertia-determining effect was conceived as autonomous, i.e., not
to be influenced by any physical circumstance whatever; it affected
masses, but nothing affected it.
<END QUOTE>
--- The Problem of Space, Ether,
and the Field in Physics, p. 279-280
<BEGIN QUOTE>
When by the special theory of relativity I had arrived at the
equivalence of all so-called inertial systems for the formulation of
natural laws (1905), the question whether there was not a further
equivalence of coordinate systems followed naturally, to say the least
of it. To put it in another way, if only a relative meaning can be
attached to the concept of velocity, ought we nevertheless to persevere
in treating acceleration as an absolute concept?
>>From the purely kinematic point of view there was no doubt about the
relativity of all motions whatever; but physically speaking, the
inertial system seemed to occupy a privileged position, which made the
use of coordinate systems moving in other ways appear artificial.
I was of course acquainted with Mach's view, according to which it
appeared conceivable that what inertial resistance counteracts is not
acceleration as such but acceleration with respect to the masses of the
other bodies existing in the world. There was something fascinating
about this idea to me, but it provided no workable basis for a new
theory.
<END QUOTE>
--- Notes on the Origin of the General
Theory of Relativity, p. 286
<BEGIN QUOTE>
I. Newton's endeavors to represent his system as necessarily
conditioned by experience and to introduce the smallest possible number
of concepts not directly referable to empirical objects is everywhere
evident; in spite of this he set up the concept of absolute space and
absolute time. For this he has often been criticized in recent years.
But in this point Newton is particularly consistent. He had realized
that observable geometrical quantities (distances of material points
from one another) and their course in time do not completely
characterize motion in its physical aspects. He proved this in the
famous experiment with the rotating vessel of water. Therefore, in
addition to masses and temporally variable distances, there must be
something else that determines motion. That "something" he takes to be
relation to "absolute space." He is aware that space must possess a
kind of physical reality if his laws of motion are to have any meaning,
a reality of the same sort as material points and their distances.
The clear realization of this reveals both Newton's wisdom and also a
weak side to his theory. For the logical structure of the latter would
undoubtedly be more satisfactory without this shadowy concept; in that
case only things whose relations to perception are perfectly clear
(mass-points, distances) would enter into the laws.
<END QUOTE>
--- The Mechanics of Newton and their Influence
on the Development of Theoretical Physics, p. 258.
<BEGIN QUOTE>
It is characteristic of Newtonian physics that it has to ascribe
independent and real existence to space and time as well as to matter,
for in Newton's law of motion the concept of acceleration appears. But
in this theory, acceleration can only denote "acceleration with respect
to space."
Newton's space must thus be thought of as "at rest," or at least as
"unaccelerated," in order that one can consider the acceleration, which
appears in the law of motion, as being a magnitude with any meaning.
Much the same holds with time, which of course likewise enters into the
concept of acceleration. Newton himself and his most critical
contemporaries felt it to be disturbing that one had to ascribe
physical reality both to space itself as well as to its state of
motion; but there was at that time no other alternative, if one wished
to ascribe to mechanics a clear meaning.
<END QUOTE>
--- Relativity and the Problem of Space, p. 360.
.
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