Re: Is electromagnetic field theory unified?
From: Franz Heymann (notfranz.heymann_at_btopenworld.com)
Date: 03/01/05
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Date: Tue, 1 Mar 2005 09:49:43 +0000 (UTC)
"JM Albuquerque" <jm.aREM.OVE@sapo.pt> wrote in message
news:38hq00F5n299jU1@individual.net...
>
> "Franz Heymann" <notfranz.heymann@btopenworld.com> escreveu na
mensagem
> news:d00161$4ij$2@sparta.btinternet.com...
> >
> > "JM Albuquerque" <jm.aREM.OVE@sapo.pt> wrote in message
> > news:38guq4F5ofml8U1@individual.net...
>
> (snip)
>
> > > Kinetic energy is a potential like a mass on a top of a table
has a
> > > gravitic potential.
> >
> > No. Not at all.
> > As a mechanical engineer you should be able to distinguish between
> > kinetic energy and potential energy.
> > It is the sum of the two which is a conserved quantity.
>
>
> That's true in the gravity context talking about free fall.
> Everybody learns that at school.
It is quite true, always and everywhere under all circumstances. It
is one of the cornerstones of physics. Gravity itself is but one of
many possible interactions, in all of which energy is conserved.
> On a rotating system the potential to produce damages (work) depends
on the
> kinetic energy. The higher the speed the higher the frequency and
the higher
> the induced voltage (Faraday's). Since voltage is a potential and
voltage is
> proportional to kinetic angular speed I've made the analogy "kinetic
=
> potential".
You really ought to undertake a complete review of your understanding
of the concepts of kinetic and potential energy.
And please do not try and obtain your information from a mechanical
engineering textbook. It has been my misfortune to have seen some
extremely bum books of that kind.
The total energy of a system is the sum of its kinetic energy and its
potential energy.
> > > Speed must change in order to energy be transmitted.
> >
> > > > > At first both of you discard the said energy requirements
> > > >
> > > > Either you have severe memory problems, or you are lying. None
of
> > > > us *ever* said that no energy is required.
> > >
> > > You have refuted that torque must be present.
> >
> > Neither of us has ever refused to acknowledge that there is a
torque
> > on a rotating magnetic dipole.
> > What we have negated is your concept that torque is energy.
>
> In a mechanical system it makes a lot of sense and I've already
explained
> why it does.
You are simply quite completely wrong.
Torque is defined as
T = r x F
Energy expended, which is work, is defined as
W = Integral F dot dr
There is no way these two quantities are the same, in spite of having
identical dimensions.
> Since rotation is mechanical in nature what I've said makes a lot of
sense
> to me and it has been very helpful to me, believe me or not, that
is.
> > > > > but I've insisted and you both spell "kinetic energy".
> > > > > I've tried to explain that kinetic energy is nothing but a
> > potential.
> > > >
> > > > Try to understand the difference between "explain" and
"claim".
> > > >
> > > >
> > > > > All that matters is torque,
> > > >
> > > > Nonsense.
> > >
> > > In fact all that matter is power:
> > > Power = torque x angular speed
> >
> > That's better.
>
> Indeed.
>
>
> > >
> > > Energy = power x time
> > > Energy = torque x angular displacement
> > >
> > > Since angular displacement has units of radians, torque is the
> > physical
> > > "force" that makes energy flow.
> > > The radiated power is the torque times angular frequency.
> >
> > No mistakes since I last said "that's better".
>
>
> From the mechanical point of view that is.
>
>
>
>
> > > > > or kinetic energy change.
> > > >
> > > > Indeed. The kinetic energy of the magnet decreases (unless
there
> > > > is a power source for the spinning).
> > >
> > > Right.
> > > We don't disagree, we don't understand each other because you
don't
> > care to
> > > understand my point of view.
> > >
> > >
> > > > > (Maybe I will try to address the problem again later).
> > > >
> > > > Please do.
> > >
> > > See above.
> > >
> > >
> > > > Your claims that "torque=energy" are a continuous source of
> > amusement
> > > > and show nicely again and again that you don't understand even
> > > > classical mechanics, much less electrodynamics.
> > >
> > > See above.
> >
> > Torque does indeed have the same dimensions as energy. However,
> > torque decidedly is *not* energy.
>
> In a rotating system, from the mechanical point of view, I insist
that
> torque times a given angular displacement is indeed a measure of the
energy
> involved in the process.
That is not torque. In your own words it involves the product of a
torque and an angular displacement.
And what you omitted to say is that it applies only in the case of the
rotation of a rigid body.
> > > > > 2 - The difference between the stationary magnetic and the
> > > > > stationary electric field.
> > > >
> > > > We have failed to explain this in your opinion? Why? We
explained
> > > > to you again and again what the similarities and differences
> > between
> > > > these two fields are.
> > > >
> > > > BTW, do you mean "static" or "stationary"?
> > >
> > > Are there any difference between "static" and "stationary"?
> >
> > Yes. Very much so. A static field is one which is independent of
> > time.
> > A stationary field is one corresponding to a standing wave. Its
> > amplitude at any point is oscillatory, and it has a constant phase
at
> > all points. I.e. it does not propagate.
>
> Thank you.
>
> (snip)
>
> > > > > You Franz Heymann, you do have a temper problem and soon the
> > > > > discussion is ruined with you.
> > > >
> > > > Indeed - Franz loses his temper in the sight of willful
stupidity.
> > >
> > > The problem is that he doesn't try to understand.
> >
> > I promise you that I try. I also confess that I frequently find
it
> > difficult to understand you, because there is so much chaff to
sort
> > from the very small amount of wheat.
> > >
> > > And there is another rule to learn something around here.
> > > First you have to make stupid claims that sound smart claims.
> > > Otherwise no discussion, no learning.
> >
> > Now there is an example of something you said which I don't
> > understand.
>
> For instance:
> I have to say that a spinning magnet doesn't radiate, knowing that
I'm
> against everybody and so looking stupid, just to have a good
discussion on
> the subject.
That is what is known as trolling.
If, indeed, you are confessing that you are a troll, I would step out
of the discussion instantly.
So, please confirm or deny whether you are just arguing for arguments'
sake or whether you are genuinely trying to learn something.
> The fact is that I want to learn why it radiates and not induces,
and so on,
> and so on.
There are an induction field as well as a radiation field associated
with a rotating or oscillating dipole in free space. The field has
one term which decreases as r^-2 and a second term which decreases as
r^-1. The former is the induction field. It has a component in the
direction of propagation. It dominates at small distances from the
oscillator. The latter is the radiated field. It dominates at large
distances, and it has components which are at right angles to each
other and to the direction of propagation
> (snip)
> > > > > Namely:
> > > > > 1 - The energy problem. Where is the source?
> > > >
> > > > The kinetic energy of the spinning magnet. Where on earth is
> > > > your problem with that?
> > >
> > > Torque.
> > > Torque is the source for the said energy.
> > > Read what Timo Nieminen wrote.
> >
> > Nobody has disputed that the energy has to be imparted to the
rotating
> > magnet by continuously applying a torque to it if it is to be
> > prevented from slowing down if it is radiating.
>
> Good.
> Now we understand each other.
It took some doing
{:-))
-- Franz "The great tragedy of science -- the slaying of a beautiful hypothesis by an ugly fact." T.H. Huxley
- Next message: Franz Heymann: "Re: Is electromagnetic field theory unified?"
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