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My definition of force!!!

My definition of force!!! - Physics Forum

My definition of force!!! - Physics Forum. Discuss and ask physics questions, kinematics and other physics problems.


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  #1  
Old 02-28-2005, 10:28 PM
TomGee
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Default My definition of force!!!



This is continuance of my previous response to PD....
PD wrote:
As I said earlier, I am not claiming that energy is a force simply on
the basis that the two are related. I have shown how the term "energy"
is a property of the universe and that force is merely an expression of
it.
or
No. As far as physics is concerned, energy is and always will be of
utmost interest to scientists and, in fact, to workers in all fields of
human endeavor.
changes
conserved
But how could you apply a force without using some energy? As a
physics quantity, "momagnitude" may be useless, but that is not the
issue at hand here. The issue is that force is the physical expression
of the quantity we call energy.
No, that's incorrect. What makes you think variable states make
quantities stand out physically?
of
analogous
it
You tell me how far it must carry in order for you to accept it and I
will try my best to get it there.
TomGee

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  #2  
Old 02-28-2005, 10:42 PM
PD
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Default My definition of force!!!


TomGee wrote:
"energy"
of

I don't know what "an expression of it" means.

Conserved
would
of

And why is that?

expression

To answer your first question, that is VERY easy. Friction holding a
car stationary on an inclined street is an excellent example of a force
expending no energy. A sign suspended by a cable from a beam is another
example. An electron bound to a proton in its ground state is another
example.

a
of

The term is "state variable" and it has a specific meaning in physics,
which I'm not sure you know. Read the thermodynamics chapters of an
introductory physics text.

if
properties
so
does

I'd like to see a quantitative accounting of how forces are the
expression of energy.
Take a closed system of your own choosing, with an internal interaction
that occurs at some point in time.
Define the energy of the initial and final states.
Show how the force is identified, quantitatively, with the "expression"
of the transfer of energy in that interaction.

Physics is a *quantitative* science, not a squishy, qualitative,
analogy-based science.

PD

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  #3  
Old 02-28-2005, 11:13 PM
Lady Chatterly
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Default My definition of force!!!

In article <1109630554.675853.72710@o13g2000cwo.googlegroups. com>
PD <[Only registered users see links. ]> wrote:

It is a little more adventurous.


They are watching tv.


Do you think that is the right pin?


Nah.


Do you think I have to wonder what attack I made while supporting you?


Nobody does is better than bush would.

--
Lady Chatterly

"Lady Chatterly is a bot, making its way all throughout usenet. It's
amusing to see some of the reactions it gets in the Google archives."
-- Asiya












































































































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  #4  
Old 03-01-2005, 12:28 AM
TomGee
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Default My definition of force!!!


PD wrote:
Angular
are
on
expression
Sorry about that, I should have said, "...merely a physical expression
of it." Does that help? If not, how about, "...a physical observation
or evidence of energy working".
is
of
fields
Sorry but that is not germane to our issue.
about
force
another
Ummm. No, all of those fail as examples. Obviously you have forgotten
about or ignored the weak force as well as the nuclear force. Got any
more you wish to try? Not so easy after all, is it? Of course not,
because no force can be applied without the use of energy, by
definition.
be
physics,
So you don't know what it means, but you try to use it in a debate?
How gauche!
but
as
be,
I
interaction
"expression"
No, you are sadly misinformed. Physics is an empirical science, but
Theoretical Physics is a quantitative science and it ignores empirical
research, basing it's concepts on pure imagination and its proofs on
pure math constructs. Every scientist is first a Theoretical Physicist
and secondly a physicist. If you would like a quantitative accounting,
do it yourself.

Take your examples above and work out the math constructs involved in
calculating your quantities, for whatever reasons you want them. They
are not relevant to the issues unless they negate or support my claims.
If your quantities can do that, let us know, please, but I would not
leave your day job if I were you, while waiting for that to happen.

TomGee

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  #5  
Old 03-01-2005, 03:01 PM
PD
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Default My definition of force!!!


TomGee wrote:
simply
expression
observation

Yes, at least it's clearer, and it's a largely empty statement. As
pointed out by me and others, coupled evidence does not constitute
identity. Velocity is required with momentum -- when you see momentum,
you will see velocity -- but the two are distinct. You can say that
velocity is evidence of momentum working, but that offers no physical
insight, nor does it reveal what is special about momentum, nor does it
explain Newton's laws more deeply.

it

I beg to differ. I maintain that the single key feature of energy is
the fact that it is a conserved quantity (and force is not). You
disputed that and said that energy has interest on its own, aside from
that feature. I asked you what that interest was, and now you say that
it's not germane. If you're going to identify forces and energy, and
dismiss the key thing that makes them distinct, I'm going to ask you
for justification of that claim.

the
a
another

How so? Each is an example of a force being applied without the
expenditure of energy. If you think otherwise, then explain the energy
expended in each case.


Haven't forgotten it. Why is it relevant?


By definition? What's the definition you're using? Please state it
carefully. If it differs from the definition that physicists
conventionally use for that term, then explain the difference.

a
one

*I* know what it means. I claim *you* don't know what it means, as
evidenced by the fact that you changed the term "state variable" to
"variable state", as though the two were the same.

to
and
empirical
Physicist
accounting,

Oh my, Tom. This previous paragraph is both illuminating about you and
deeply saddening. I don't know where you got this impression about
theoretical physics. It is not only wrong, but deeply misguided. If you
are pursuing your ideas in physics with this mentality, then you have
divorced yourself from science.

In the end, it matters less whether your ideas are right or wrong, than
how you pursue your ideas in a scientific way. It is fine and good
science to be wrong but to have gotten to the wrong answer in the
proper way. It is bad and poor science even to be right, but not have
any concept how to develop the idea scientifically.

They
claims.

Tom, you will fail in any attempt at theoretical physics if you cannot
do a quantitative calculation based on your ideas. That is a simple and
plainly stated fact. If you do not believe that, then I suggest you
choose ANY professional theoretical physicist that has published in
refereed journals and look at any two papers by that physicist in those
journals. Any college science library will have a wealth to choose
from. If you can find a *single* theoretical paper that does not do
calculations, then I will recant my words. However, I'm confident that
you will find that I am right, and that this will be a sobering
experience for you.

PD

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  #6  
Old 03-01-2005, 06:54 PM
TomGee
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Default My definition of force!!!


PD wrote:
they
momentum,
it
But momentum is a quantity that expresses the motion of a body and its
resistance to slowing down. Here you are again referring to properties
while my claim refers to the physical evidence of energy. As you
correctly point out, relating velocity to momentum offers no physical
insight, but that's because velocity is a vector comprised of more
quantities.
Energy
be
Well, I disagree, as the truth seems to be a matter of opinion. I
suspect that you are making it an issue simply to veer us off-track
into meaningless blind alleyways which are at the least a waste of
time. Howver, in case you are serious about it, I agree that force is
not a conserved quantity; that is why it is a physical expression of
the quantity we call energy.
from
that
Ok, see above for my justification of my claim.
force
a
holding
energy
Ok, let's take your friction example first. Friction is resistance
encountered by an object moving relative to another object with which
it is in contact, and resistance is a force that opposes or slows down
another force.

A sign suspended from a beam by cable is under the influence of the
force of gravity on Earth.

I am not as well-studied in nuclear physics as I would like to be, but
I believe there has been put forth a notion explaining why an electron
in its ground state should be bound to the nucleus, although I cannot
remember it now. I would think that is due to the fact that the
electron in its ground state is in its lowest energy state and thus
most vulnerable to the attractive (magnetic?) force of the positive
proton.
not,
FORCE
9. physics[:] influence that moves something: a physical influence
that tends to change the position of an object with mass, equal to the
rate of change in momentum of the object. Symbol F
Microsoft® Encarta® Reference Library 2005. © 1993-2004 Microsoft
Corporation. All rights reserved.
still
to
make
an
straight,
them
to
where
but
on
and
you
No, PD, it is you who is sadly misinformed as to the difference between
real physics and Theoretical Physics. No one ever explained to you
that physics is the study of the physical nature of things and that
theory is born of our imagination from observations of the physical
world? I refuse to refer anyone to read anything because I dislike
that myself, but in your case I would refer you to any common usage
dictionary or a physics reference work to get your definitions
straightened out. Or ask your mentor(s), or any physics professor. Or
maybe someone reading this will speak up and clear that up for you.
than
That may be true for you, but for me it is more important to arrive at
convictions which satisfy my own yearning for answers to the queer
effects we observe in our world, and to do that with straight thinking.
Due to that, I often find myself at odds with those who struggle to
conform with and defend accepted theory, who would not recognize a good
idea even unless most others agreed with it, and who thus are doomed to
an existence where original thought is impossible.
well, certainly you're entitled to your own opinions about that.
in
not
cannot
That is the conformist view expounded throughout these science ngs, but
it is a false view since theoretical physics is limited only to what
could be while real physics requires conformance to observed effects.
My model proposes ideas which fulfill both requirements and more
importantly, which satisfy my yearning for rational explanations of the
observed phenomena of our universe. I am so happy with my explanations
to myself that I have found the peace of mind I sought for many years
ever since my first science elective revolted at the dearth of straight
thinking about our physical world.
If it were a fact, I would have no trouble believing it, but it is only
an opinion. Besides, I have no expectations of my ideas being
well-considered in my time, as history shows humans don't learn from
history and they don't learn well until long after the truth was first
proposed.
those
that
I appreciate your sentiments, PD, but I think that you simply support
what I just said about current populations, that they have such
conformist restrictions as to prevent good ideas from ever reaching the
floor of debate in any particular science. It has always been thus,
and I guess it always will be until our brains evolve to higher levels
where straight thinking will prevail and be better appreciated. Til
then, those like me are stuck in no-go land unless we bow to the
conformist demands of the disciplines to which we wish to contribute.

TomGee

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  #7  
Old 03-01-2005, 08:51 PM
PD
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Posts: n/a
Default My definition of force!!!


TomGee wrote:
the
term
physical
does
its
properties

More quantities than momentum? Explain.

in
that
will
is
is

How can something not conserved be the physical expression of something
that is conserved? The conservation IS the physical expression of the
energy!

and
you
physically
a
As
not
a

Moving? No, that's only kinetic friction. The case that I presented was
a case of static friction. Note the car is on a hill but it is NOT
sliding. It is friction that is holding it even though it is not
moving. I'll give you another example. Pick up a can of peas holding
the sides of the can only. What is the force that keeps it from
falling? What is the energy expended in that process?

down

Actually, no. Did you realize that it is friction that makes a car move
*forward* when you press the gas pedal?


But it is not moving. There is no expenditure of energy! If so, what is
it?

but
electron

Well, this isn't nuclear physics, and you're right, you're rusty on it.
But again, there is a force that is keeping the electron bound to the
proton, but there is no energy expended. It is stable, and the
electron's energy doesn't decay away.

the

Note that this is a rather weak definition, because the predicate is
really the definition of a *net* force rather than force in general.
That's what one gets for putting one's faith in a lexicographer rather
than a physicist. Regardless, there is nothing in this definition that
requires the expenditure of energy. Indeed, in the examples previously
posted, we cited instances where there is unquestionably a force at
work but no change in energy.

systems.
force
is
of
debate?
energy
us
it
qualitative,
have
between
Or

I beg to differ, and I'm speaking as a professional physicist. And I
suggest to you that a better source for understanding the meaning of
"real physics" and theoretical physics is to ask a practicing
physicist, not a common usage dictionary (note the problem we had with
Microsoft's definition of "force") or a broad-audience physics
reference work.

at
thinking.

And the straight thinking has to be confronted with empirical facts
routinely. Straight thinking can often lead to conclusions that seem
very appealing but have nothing to do with the way nature really works.

good
to

Again, I think you'll find that novel ideas are often warmly received,
provided that the originators have done some of the required legwork to
validate them at at least a preliminary level, have shown them to be
consistent with known observations, and have proposed concrete tests
with which to shake the ideas out. Ideas that do not come with this
"portfolio" are rarely considered seriously, even if in the end they
turn out to be right. This is not criminal. This is the way it should
be.

have
involved
happen.
but

Again, you have a sad misconception about theoretical physics. If
theoretical physics were simply musing about constructs which have some
appeal but are not bound by observed effects, then theoretical physics
would be indistinguishable from science fiction, theology, metaphysics,
or astrology. I assure you that theoretical physics involves more than
that.

the
explanations
straight

Well, I'm not going to probe into a personal history that set you on
this misguided path. Iconoclasm is fine and dandy. Pointless iconoclasm
seems like a waste to me.

only
first

By all means, piddle away. And you'll no doubt understand why readers
of your ideas will continue to offer the critique that you have not
satisfied the basic requirements for an idea to come to fruition.

the
levels

As you say, people don't learn from history, and often because they
refuse to read about it. You are one in a long line of
iconoclasts-for-iconoclasm's-sake who have not learned what doing
science is about, are self-satisfied that what they are doing is
science, and are convinced that what they have in their heads is
valuable and insightful. Yet you don't know the history of those that
have made a mark in physics and those that have not, and why.

Any vocation -- and I mean any -- requires toil that appears unseemly
to the principle task. Physics is no exception. If it isn't hard, and
it isn't frustrating, and it doesn't require you to do things you don't
want to do or feel ill-equipped to do, and it doesn't occupy more time
than seems worthwhile, then it isn't physics.

PD


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  #8  
Old 03-01-2005, 09:09 PM
Tom Capizzi
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Posts: n/a
Default My definition of force!!!


"TomGee" <[Only registered users see links. ]> wrote in message
news:1109703244.187479.204890@o13g2000cwo.googlegr oups.com...

PD wrote:

[snip]

[begin TomGee]
But momentum is a quantity that expresses the motion of a body and its
resistance to slowing down. Here you are again referring to properties
while my claim refers to the physical evidence of energy. As you
correctly point out, relating velocity to momentum offers no physical
insight, but that's because velocity is a vector comprised of more
quantities.
[end TomGee]

I think you're confused about momentum. It takes the same amount of
force to reduce momentum, P, by delta P in a given delta t, regardless of
the actual magnitude of the initial momentum. The property of resistance
to change of momentum is inertia, which is a result of mass. Also, this
property (inertia) applies to attempts to increase velocity (or momentum)
as well as decrease.

[snip]

[begin TomGee]
If it were a fact, I would have no trouble believing it, but it is only
an opinion. Besides, I have no expectations of my ideas being
well-considered in my time, as history shows humans don't learn from
history and they don't learn well until long after the truth was first
proposed.
[end TomGee]

You are clearly mistaken here, as evidenced by the subject of this
newsgroup.
Einstein was clearly well-considered in his own time, and he is not the only
example. A really brilliant idea catches on a lot quicker than some muddled
theory.


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  #9  
Old 03-01-2005, 11:15 PM
TomGee
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Default My definition of force!!!


Tom Capizzi wrote:
its
properties
regardless of
I don't claim to know all there is about it, but the fact that it is a
quantity makes it a property and that is my point, that properties are
not physical evidence of energy. An amount of force is also a
quantity; thus, I am not saying that a quantity of force is physical
evidence of energy, but that any observed exercise of power as a force
is indeed.
Again, resistance is a force that opposes or slows down another force.
Inertia is the property of a body by which it remains at rest or
continues moving in a straight line unless acted upon by a directional
force. [Microsoft® Encarta® Reference Library 2005. © 1993-2004
Microsoft Corporation. All rights reserved]

Thus, resistance is not a property but a force. Inertia is a property
of an oject by which it wants to stay as is. As a property, it cannot
be physical evidence of energy at work.
momentum)
Yes, but what is your point?
only
first
the only
Maybe people were smarter then than they are today?
I don't claim to have brilliant ideas, only ideas born from straight
thinking which questions certain claims from emperors who roam the
streets naked. My ideas are difficult to understand, but I think
that's due at least as much to the inability of many to react well to
change as they are difficult to explain. At what point do you say,
"let us suppose he is right about that, how can it be defended?",
instead of the usual, "you must conform to my idea of what a good idea
is or you will fail to impress anyone with your wild ramblings."

For anyone to believe that good ideas must be shown by or must contain
math constructs is conformist to the nth degree simply because and
especially since math is the way of Theoretical Physics and not
empirical research. AE taught us that math can be manipulated toward
any end, true or false, and we know that logical reasoning can also be
manipulative, but many seem to forget that and they accept math as
Truth and Fact when presented by those whom they admire as their
mentors or teachers. Think how many trudged off with their heads bowed
when their hero AE admitted his errors. What made them think he could
do no wrong? How could they be so gullible when the word is not even
in the dictionary?

Straight thinkers will take an idea - any idea - and review it to the
end of the trail it leads to which ends at either that point where it
can be deemed invalid or that point where it must be defended against
detractors.

TomGee

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  #10  
Old 03-02-2005, 04:56 AM
TomGee
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Default My definition of force!!!


Geraldine Hobba wrote:
news:1109718918.946975.264110@o13g2000cwo.googlegr oups.com...
physical
SNIP
a
are
Yes, Bill, if you had read the previous posts in this thread you would
have better known what has already been discussed. To come in midway
and rehash stuff already covered shows a selfish side not many would
want to show in public.
that naturally results form Noethers famous theorem - it is the
conserved charge related to time symmetry. It conservation is
logically equivalent to time invariance of the lagrangian.
This issue cares not where it naturally resulted from, Hobbit, nor what
it is related to nor logically equivalent to whatever of whatever.
Energy has already been defined as a quantity in this thread.
force
No, you're wrong again, Bill, force has already been defined previous
to your entrance into this thread as a physical influence that tends to
change the position of an object with mass, equal to the rate of change
in momentum of the object.
inertial frame which is logically equivalent to Newton's famous third
law.
Yes, and so what?
SNIP
force.
directional
Therefore, inertia is a property and as a property it cannot also be an
exercise of the power of the energy which is inherent in the said body.
SNIP non-relevant statements
property
cannot
Then why do you do it?
idea
contain
be
[Only registered users see links. ]
That may be the opposite of what he thought, but it is what he taught
the world when he used math to prove his static universe. Also, you
imply that the quote below is from AE hisself - shame shame shame! It
is only an opinion by others who are motivated to publish or perish.
and physical thinking which goes a long way toward explaining why so
few mathematicians have made important contributions to physics in the
20th century. Pure mathematicians do not think about the equations of
physics in the same way as a physicist does. They are concerned only
with the structure of the equations and the formal rules for
manipulating them.
That is precisely the definition of the science of Theoretical Physics
which I gave previously in this thread, which you obviously did not
read.
or processes; they are only partial representations of the physicists'
knowledge, so to improve a representation they may alter the equations
in ways that violate mathematical rules. Both Einstein and Heisenberg
were masters at this.
So how is the above exactly opposite to what I said?
Einstein was developing his general relativity theory, the
mathematician Hilbert expressed the opinion that Einstein was
mathematically naive. I have heard a similar opinion about Heisenberg
expressed by one of his students in later years. Mathematics played an
essential role in Einstein's thinking, but, as mathematical physics
goes, the mathematics in all his great papers is comparatively simple.
His forte was in analyzing the physical meaning of the mathematics.
Indeed, such analysis is generally characteristic of the best work in
theoretical physics. I have heard the Nobel laureate Richard Feynman,
himself a true mathematical virtuoso, express this opinion forcefully,
asserting that the value of a paper on theoretical physics is inversely
proportional to the density of mathematics in it.'
Again, isn't that what I was saying?
that makes a great physicst. What is happening was also expressed
elequontly by Cleick in a famous remark about Feynman, Eisntein and
Landau
[Only registered users see links. ]
twenty-three ... there was no physicist on earth who could match his
exuberant command over the native materials of theoretical science. It
was not just a facility at mathematics (though it had become clear ...
that the mathematical machinery emerging from the Wheeler-Feynman
collaboration was beyond Wheeler's own ability). Feynman seemed to
possess a frightening ease with the substance behind the equations,
like Einstein at the same age, like the Soviet physicist Lev Landau -
but few others.'
This is apparently the opposite of what I said, but it's just opinion
that Wheeler was limited while Feynman was beyond greatness with his
overwhelming math and substance. So why did he need Wheeler if he was
so great? Opinions are subjective beyond belief when they voice
admiration for someone the author considers god-like.
that makes a great physicist - not the arbitrary manipulation of
mathematics.
Ah Ha Ha! That is pure opinion from you using someone else's words!
How crass of you.
admitted his errors.
All of them. Every single one of them, none of which are specifically
germane to this discussion.
"Gullible" is the word I referred to which does not appear in
dictionaries nor in reference works.
inclination to - understand something before criticizing it.
But that is exactly what you did when you wrote the above without
bothering to read what had been discussed before you entered the fray!
You barged right in with the utmost misunderstanding of the issues and
you proceeded to criticize everything of which you had no undertanding!
One thing I can always count on from you, Hobble, is a good laugh.

TomGee

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