Re: My definition of force!!!

From: PD (pdraper_at_yahoo.com)
Date: 03/07/05 

Date: 7 Mar 2005 06:54:22 -0800

TomGee wrote:
> PD wrote:
> > TomGee wrote:
> > > PD wrote:

[snip]

> > > >
> > > Ok, so that means you believe gravity acts over a displacement,
but
> > > when there is none, i.e., no amount of movement in a particular
> > > direction, gravity is not present or not working at that
particular
> > > time and no energy is being expended by the gravitational force
> then?
> >
> > No, I did not say that, either. When there is no displacement, the
> > force can very well be present and acting in full force, but there
is
> > no energy expended. It is only you who are wedded to the idea that
> zero
> > energy expended means zero force.
> >
> >
> It is not only me, but most scientists agree with me, as shown below.
>
> "Usually, several forces act on an object at once. If multiple forces
> combine to give a net force that is zero, then the object will not
> accelerate; the object will either remain motionless or continue
moving
> at a constant velocity. For example, if a person pushes a shopping
cart
> with a force equal in magnitude to the force of friction that opposes
> the cart's motion, the forces will cancel, giving a net force of
zero.
> As a result, the cart will move down the aisle with a constant
> velocity. If the person suddenly stops pushing the cart, the only
force
> acting on the cart is the frictional force. Since the net force is no
> longer zero, the cart accelerates: its velocity drops to zero."
> Microsoft ® Encarta ® Reference Library 2005. © 1993-2004
Microsoft
> Corporation. All rights reserved.
> Note that the net force is non-zero whenever any force is acting on
the
> cart, and so that means that zero energy expended means zero force.

I see. So apparently you are having difficulty reading and
understanding even Microsoft Encarta blurbs. No where in there does it
say that the net force is nonzero whenever any force is acting on the
cart. In fact it says:
"If multiple forces combine to give a net force that is zero..."
Namely, here is a case where there are nonzero forces present and they
combine to give a zero net force. Notice too in the next sentence:
"For example, if a person pushes a shopping cart with a force equal in
magnitude to the force of friction that opposes the cart's motion, the
forces will cancel..." This does NOT mean that because the net force is
zero, then the person's push must be zero or that the friction must be
zero. Quite the contrary, anyone that has pushed a shopping cart
recently knows that both forces are definitely NONzero. And yet there
is no change of energy of the cart!

What is NOT captured in the Encarta blurb (because its editorially
required brevity demands that a full explanation must be sacrificed)
are OTHER circumstances in which a force does not lead to energy
expended: a) cases where there is no displacement whatsoever, b) cases
where the displacement is perpendicular to the direction of the force.

> The net force left on the cart is the frictional force which is
caused
> by the gravitational force pulling the wheels to the ground.
> > > >
> > > >
> > > > Look up the work-energy theorem.
> > > >
> > > > If the force of gravity is acting on an object, but there is NO
> > > > displacement in the direction of the force of gravity, then
there
> > > will
> > > > be NO energy expended by that force.
> > > >
> >
> I show above where that is patently false.

You realize, of course, that you are denying Newtonian physics? Look up
the work-energy theorem. You may need something a bit more
comprehensive than Encarta.

Secondly, the Encarta blurb is NOT in contradiction with what I said.
If you think it is, explain.

> >
> >
> > > I have already disposed of your coffee cup and cable examples, so
I
> > > will deal with your orbiting moon philosophy.
> >
> > You have not disposed of the coffee cup and cable examples. Both
are
> > cases where there is a force present and no energy expended. In the
> > sign-on-a-cable example, you actually declare that the sign should
> heat
> > up due to the energy expended by gravity -- which is something that
> is
> > easily experimentally testable, and in fact common experience (that
> is,
> > everyday experiments) rule out.
> >
> >
> No, I have said no such thing.

You deny saying the following?
============
> > > > > > > A sign suspended from a beam by cable is under the
influence
> > > > > > > of the force of gravity on Earth.
> > > > > > > But it is not moving. There is no expenditure of energy!
If so,
> > > > > > > what is it?
> > > > > The force of gravity is pulling on it continuously.
> > > > I see. And where does that energy go? Does it heat up the sign?

> > > It is conserved, that's where it goes.
> > Wow! You really believe that, and it doesn't bother you? The longer
the
> > sign just hangs there, the warmer it gets?
> If the sun is shining on it....
===========

> >
> > >
> > > Were you not taught in hs that the moon is caught in the pull of
> the
> > > Earth's gravitational field and that is what keeps it in orbit,
but
> > if
> > > suddenly there were no attractive force then the moon would just
> keep
> > > on going into space away from Earth?
> >
> > I did not say that the force was zero. I said that the force was
> > present but the energy expended was zero, because there is no
> > displacement in the direction of the force. It is only you who is
> > wedded to the mistaken idea that if the energy expended is zero,
the
> > force must be zero.
> >
> >
> Again, see above where I point out your error.

No error pointed out. How does the Encarta blurb point out an error in
my statement?

[snip]
> >
> >
> > > My model is just a series of alternative explanations of observed
> > > phenomena which begins with time and progresses through the
> creation
> > of
> > > light. It resolves some current explanations of issues which
have
> > led
> > > us all into dead-end alleyways from which we cannot get out.
> >
> > Name one dead-end.
> > Name your theory's explanation that is successful where the current
> > model has no consistent explanation.

Lack of response noted.

> >
> > > Plus it
> > > provides fresh looks at the issues and a chance for readers to
get
> > > ideas on their own and perhaps come up with even better ideas
than
> > > mine.
> >
> > Ideas are worthless until they have shown some bearing on reality 

--
> > that is, that they extend our predictive powers.
> >
> > > >
> No, not so.  New ideas can be worth their weight in platinum, else
> corporations would not spend resources to hold brain-storming
sessions
> where participants are encouraged to submit anything that comes into
> their minds during the sessions, no matter how imaginative they may
be.
You know why they do that? Because the people that they invite to those
sessions that have demonstrated to have ideas that are 1) productive,
2) based on reality and previous lessons learned, 3) and are still
imaginative. All three are required. Those that produce ideas that
satisfy only one of these criteria are not invited back to those
sessions.
You have such a naive and misguided view of the market value of free
and unconstrained imagination, Tom.
>  Ideas are all that Theoretical Physics holds dear since they disdain
> experimental research.  So, again, you are wrong.
Disdain?! Where the HELL did you get that impression? To which
theorists have you asked this question and who remarked that they
disdain experimental research? Please be specific, because I've worked
as an experimentalist side-by-side with theorists, applying our
different skill sets to the same problems. I can tell you from personal
experience, Tom, that you are plainly talking out of your rear end on
this one. In fact, I know several theorists that would be deeply
offended by this comment.
> > > >
> > > >
> SNIP
> >
> > > Um, what empirical evidence is that?
> >
> > Precession of the perihelion of Mercury, synchrotron design and
> > operation, GPS satellite corrections required by SR and GR and not
> > predicted by classical physics, predictions of black holes and the
> > evidence by which we would see evidence of them, curvature of light
> in
> > a gravitational field and gravitational lensing of distant
galaxies,
> > the expansion of the universe.... Shall I go on? There's a rather
> long
> > list.
> >
> > > >
> No. I asked for the one you claim overthrows classical physics, which
> is the one you failed to list.
All of those listed. Classical physics has predictions about precession
of perihelion of Mercury, and it's wrong. Classical physics has
predictions about synchrotron design, and it's wrong (which was
discovered in early cyclotrons before it was too late, thank goodness).
Classical physics has predictions about the clock behavior on GPS
satellites, and it's wrong, and the SR and GR-guided corrections to
classical algorithms are now built into GPS satellites. Classical
physics not only does not predict black holes but predicts that they
should not exist, and it's wrong. Classical physics does not predict
gravitational lensing, and in fact says it should not happen, and it's
wrong. Shall I go on?
> >
> > > >
> > Has it ever crossed your mind that "honest research, theoretical or
> > empirical" and "consistent with the way I view our world" are
> mutually
> > incompatible?
> >
> > > >
> Yes, of course.
I believe you should investigate that possibility more strongly.
> > > >
> > > >
> SNIP
> > >
> > > ...I have never
> > heard
> > > of a real physicist ever arguing that an encyclopedia was wrong,
> >
> >
> > I don't think you've ever asked the question directly.
> >
> >
> Wrong again.  You're running out of bullets.
Whom have you asked? Be specific. And I've just started, not even
reloaded once yet.
> >
> >
> > Why don't you
> > post a link to an Encarta definition, or quote it directly, and ask
> the
> > physicists here think it is correct? Note there is a similar
approach
> > by someone named Paulps in these newsgroups who is receiving
exactly
> > that criticism from the physicists in the group.
> >
> >
> I have done that very same thing.
Reference please.
> >
> >
> > >  but
> > > plenty of them argue about many authors works and their ideas.
> Your
> > > argument on this subject has failed each time you have tried it.
> You
> > > should abandon it.
> >
> > How has my argument failed? What constitutes success to you?
> >
> > >
> Your argument that encyclopedias are less worthy references than
those
> in FAQs and physics books failed because the facts in Encarta and
> Wikkipedia are supported by authorities in the field, even if not by
> you.
Which authorities? Cited authors and reviewers for Encarta, please...
(I note that you have not once posted a Wikkipedia reference in this
discussion, so your reference to Wikkipedia is irrelevant.)
And what about my arguments about your faulty reading and understanding
of Encarta blurbs? How have my arguments there failed? What constitutes
success to you?
>  
> TomGee
PD

Relevant Pages

  • Re: My definition of force!!!
    ... >> energy expended means zero force. ... the cart will move down the aisle with a constant ... You realize, of course, that you are denying Newtonian physics? ... the Encarta blurb is NOT in contradiction with what I said. ...
    (sci.physics)
  • Re: My definition of force!!!
    ... gravity is not present or not working at that particular ... > energy expended means zero force. ... the cart will move down the aisle with a constant ... Classical physics is soundly based on ...
    (sci.physics)
  • Re: My definition of force!!!
    ... gravity is not present or not working at that particular ... > energy expended means zero force. ... the cart will move down the aisle with a constant ... Classical physics is soundly based on ...
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  • Re: My definition of force!!!
    ... gravity is not present or not working at that particular ... > energy expended means zero force. ... the cart will move down the aisle with a constant ... Classical physics is soundly based on ...
    (sci.physics.relativity)
  • Re: My definition of force!!!
    ... gravity is not present or not working at that particular ... > energy expended means zero force. ... the cart will move down the aisle with a constant ... Classical physics is soundly based on ...
    (sci.physics)