sophiecentaur said:
Electrons round atoms? Whilst it's "going round", do you think it's reading about Quantum Mechanics and Schroedinger's wave equation.
No it wouldn't, at best, probabilistic approximation can tell it only that it moves(yes, in orbital configurations), not how to move(how to generate its motion).
Drakkith said:
I don't know what you mean by all of this. "Perceptual level of understanding"? What exactly are you asking for?
What I did in the opening post of this thread and what I explained in the "what is energy" thread: I'm asking for the referents of the concept, where those referents are specific entities, their relationships(causal, spacial, temporal, etc) and perceivable attributes.
And where those referents are not equivocal in their description of the concept.
"Quantity of motion" and p=mv, are not such explanations - do not lead to understanding; do not ground the concept in reality.
Drakkith said:
There is no CURRENT cause of motion other than the fact that the Earth was formed from collapsing material that already had rotation from the collapse. The source of that was, in the end, the Big Bang yes.
In other words, it rotates SOMEHOW. I don't see where you get the confidence to tell me that I'm somehow deluded about the evidence of Newtons first law.
Drakkith said:
As to WHY I believe this, it is because current evidence supports maintsream science.
In other words, because it is the most popular view. You shouldn't confuse evidence, with interpretation and inference from it; and reality with the consensus that builds around one such interpretation.
Something which proved this fact to me; the following quote is from Lanzcos' "The Variational Principles of Mechanics":
1.The variational approach to mechanics. Ever since New-
ton laid the solid foundation of dynamics by formulating the laws
of motion,the science of mechanics developed along two main
lines.One branch,which we shall call “vectorial mechanics,”
starts directly from Newton’s laws of motion.It aims at recog-
nizing all the forces acting on any given particle, its motion being
uniquely determined by the known forces acting on it at every
instant.The analysis and synthesis of forces and moments is
thus the basic concern of vectorial mechanics.
While in Newton’s mechanics the action of a force is measured
by the momentum produced by that force the great philosopher
and universalist Leibniz a contemporary of Newton advocated
another quantity, the vis viva (living force), as the proper gauge
for the dynamical action of a force. This vis viva of Leibniz
coincides, apart from the unessential factor 2 -with the quan-
tity we call today “kinetic energy.” Thus Leibniz replaced the
"momentum” of Newton by the“kinetic energy.” At the same
time he replaced the “force” of Newton by the "work of the
force.” This "work of the force” was later replaced by a still
more basic quantity, the "work function.” Leibniz is thus the
originator of that second branch of mechanics, usually called
"analytical mechanics”,which bases the entire study of equili-
brium and motion on two fundamental scalar quantities,the
“kinetic energy”and the "work function,”the latter frequently
replaceable by the“potential energy.”
Since motion is by its very nature a directed phenomenon,it
seems puzzling that two scalar quantities should be sufficient to
determine the motion.The energy theorem,which states that
the sum of the kinetic and potential energies remains unchanged
during the motion,yields only one equation,while the motion of
a single particle in space requires three equations;in the case of
mechanical systems composed of two or more particles the dis-
crepancy becomes even greater.And yet it is a fact that these
two fundamental scalars contain the complete dynamics of even
the most complicated material system,provided they are used
as the basis of a principle rather than of an equation.
[Later Lanzcos writes]
The vectorial and the variational
theories of mechanics are two different mathematical descriptions
of the same realm of natural phenomena.Newton’s theory bases
everything on two fundamental vectors:"momentum”and
“force”;the variational theory，founded by Euler and Lagrange，
bases everything on two scalar quantities:“kinetic energy”and
"work function.”Apart from mathematical expediency，the
question as to the equivalence of these two theories can be raised.
In the case of free particles，i.e.particles whose motion i s not
restricted一by given "constraints，”the two forms of description
lead to equivalent results.But for systems with constraints the
analytical treatment is simpler and more economical.
What I wish to show specifically, by these quotes, is that the terms we use(which seem otherwise so matter of fact), even in physics, represent specific interpretations(which necessarily holds the possibility of error) of reality, sometimes with the primary aim of internal theoretical consistency and then an accurate identification of physical reality. For this reason I have taken the attitude(and I suggest it to you), that my primary goal in learning physics, should be to understand the extent to which such concepts as momentum/work/energy refer to things in reality or things in themselves or are approximation(incomplete in their description).
