"Don Kelly" <dhky@[EMAIL PROTECTED]
> wrote in message
news:Wcl8k.50123$gc5.12925@[EMAIL PROTECTED]
>
>
> ----------------------------
> "Bill Miller" <billmillerkt4ye@[EMAIL PROTECTED]
> wrote in message
> news:_s78k.136843$SV4.71669@[EMAIL PROTECTED]
>>
>> "Don Kelly" <dhky@[EMAIL PROTECTED]
> wrote in message
>> news:rqU7k.26648$Jx.4753@[EMAIL PROTECTED]
>>> ----------------------------
>>> "Bill Miller" <billmillerkt4ye@[EMAIL PROTECTED]
> wrote in message
>>> news:kpR7k.67754$102.31400@[EMAIL PROTECTED]
>>>>
>>>> "Spaceman" <spaceman@[EMAIL PROTECTED]
> wrote in message
>>>> news:s7udnaL83ceu-8DVnZ2dnUVZ_tHinZ2d@[EMAIL PROTECTED]
>>>>> Bill Miller wrote:
>>>>>> "Spaceman" <spaceman@[EMAIL PROTECTED]
> wrote in message
>>>>>> news:MtGdnScK_upVu8DVnZ2dnUVZ_q7inZ2d@[EMAIL PROTECTED]
>>>>>>> Bill Miller wrote:
>>>>>>>> For example, for many years, Newton's Law fell into the "Law"
>>>>>>>> category. Not anymore.
>>>>>>>
>>>>>>> Sorry to quibble Bill,
>>>>>>> What law of newtons became not a law anymore?
>>>>>>> Perpetual motion designers all over the world would like to know
>>>>>>> so they can "break" all of his laws by simply jumping over one.
>>>>>>> :)
>>>>>>>
>>>>>>> --
>>>>>>> James M Driscoll Jr
>>>>>>> Spaceman
>>>>>>>
>>>>>>>
>>>>>>> Hello Spaceman. No quibble... just an example of how teaching has
>>>>>>> not kept pace with reality. Here goes:
>>>>>>
>>>>>> One of the fundamental laws of mechanics is Newton's law of action
>>>>>> and
>>>>>> reaction, usually stated as : "Whenever a body exerts a force
>>>>>> (action) on a second body, the second body exerts an equal and
>>>>>> opposite force (reaction) on the first body."
>>>>>>
>>>>>> Suppose that a stationary mass is located in the gravitational
field
>>>>>> of another, distant stationary mass.The two m***** exert equal and
>>>>>> opposite forces on each other. (Action and reaction) Let us now
>>>>>> allow one mass to move under the action of the field of the other
>>>>>> mass. ut the second mass, being far away, does not yet "know
>>>>>> that the first mass has moved. (gravity -- like light -- cannot
>>>>>> propagate instantaneously.) The second body continues to experience
>>>>>> the same force as before.
>>>>>
>>>>> Bill, I am sorry you have been fooled by the described situation
>>>>> Newtons force theory has to include every object in between
>>>>> also.
>>>>> When every action-reaction of the object is considered, it has never
>>>>> been
>>>>> wrong.
>>>>> The example given is "ignoring" action-reaction of all in between
>>>>> the two objects.
>>>>>
>>>>>> In other words, the forces are now unequal in magnitude and
direction
>>>>>> and Newton's action/reaction law no longer holds! Further, this
>>>>>> situation also is in conflict with the very basic law of
conservation
>>>>>> of momentum.
>>>>>
>>>>> Every action/re-action in between have balanced.
>>>>> Forces have caused "objects that would transfer the force
>>>>> to transfer to a different direction, and not enough force
>>>>> was transmitted all the way to cause the re-action you were hoping
>>>>> for.
>>>>> Newton still holds true if each and every action-reaction is
>>>>> considered
>>>>> in between.
>>>>>
>>>>>> For a detailed analysis of this, and other Newtonian flaws, please
>>>>>> see
>>>>>> Jefimenko's "Causality, Electromagnetic Induction and Gravitation"
OR
>>>>>> "Gravitation and Cogravitation."
>>>>>
>>>>> Again,
>>>>> This is not a newton flaw, it is a flaw of the understanding of the
>>>>> newton
>>>>> law.
>>>>> Each and every single object in between must be considered.
>>>>> You can not ignore the action-reactions that take place in between
>>>>> the two objects like such is being done to come up with
>>>>> the supposed violation.
>>>>>
>>>>> Try this one in a much simpler form but almost like the gravity
>>>>> problem...
>>>>> Lets use air.
>>>>> Air between two objects on the ground.
>>>>> Would the air transfer all the motion of an object
>>>>> that is 5 ft away from another object?
>>>>> No, simply because all the force of the action-reactions
>>>>> are diverted by the air but all action re-action of the air
>>>>> follows Newton's law very well.
>>>>> the same holds true for gravity.
>>>>> :)
>>>>>
>>>>>> BTW, Timo questioned my assertion that F = MA was also "leaky." I
>>>>>> THOUGHT that the above also affected this equation. After further
>>>>>> review... Timo's right... so far!
>>>>>
>>>>> Action-reaction of Newton law still holds true if
>>>>> all such action-reactions in between are considered.
>>>>>
>>>>>
>>>>>> I hope this helps!
>>>>>
>>>>> I hope what I babbled probably too many times just now,
>>>>> helps you understand that Newton still holds fine and no
>>>>> problem has occured that Newton has been proven wrong
>>>>> in such.
>>>>> (Missing forces is the only way he is ever proven wrong)
>>>>> and missing forces only proves that someone is not following
>>>>> Newton the way they really should.
>>>>>
>>>>> After all any force at all, is a force and not only the ones
>>>>> Newton haters want to pick are the only forces.
>>>>> :)
>>>>>
>>>>>> BTW, yes, a glass is simultaneously 20% empty and 80% full, but
>>>>>> entirely too many people (IMNTBHO) ignore the fullness and
>>>>>> concentrate only on the empitiness. And that's kinda sad!
>>>>>
>>>>> Yes, it is sad..
>>>>> I always try to think of both sides of the story.
>>>>> It is much safer to do so also.
>>>>> :)
>>>>>
>>>>> I am sorry for babbling but I have never seen Newton's
>>>>> Laws to be wrong.
>>>>> and that is why I always follow him and think about each
>>>>> and every force (action-reaction) that could occur.,,
>>>>> also if I don't follow such being mechanically minded... I could be
>>>>> killed.
>>>>> Newton has saved my life a few times.
>>>>> I am sure he probably has saved a lot of peoples lives by coming
>>>>> up with such beautiful laws that have not actually been broken ever.
>>>>> :)
>>>>>
>>>>> --
>>>>> James M Driscoll Jr
>>>>> Spaceman
>>>>>
>>>>>
>>>> I think I understand your point, but in the case that I described,
>>>> there is nothing in between the two m***** but vacuum. Are you
>>>> postulating some special property of vacuum that instantaneously
>>>> transmits force vector information from a perturbed mass to a mass in
>>>> the same field? If so, I'd like to learn more about that!
>>>>
>>>> If not, then there will be a delay between when a mass is perturbed
and
>>>> when the perturbation is sensed..And that delay is not explicit in
any
>>>> of Newton's laws.
>>>>
>>>
>>>
>>> Put a bunch of ball bearings in contact with each other in a row. Tap
>>> the first one and not that the last one does not instantaneously
react.
>>> At each contact point, assuming the bearings are incompressible there
is
>>> a local action/reaction equivalence but the time for this to be
>>> transferred to the end is dependent on the speed of sound in the
>>> bearings. Essentially a travelling wave. No need to go to deep space
to
>>> see a delay. Does this make Newtons 3rd law invalid?
>>
>> GREAT example. Let's think about this.
>>
>> We hit the first ball. Some time later, the last ball moves.
>>
>> Newton says: "For every action, there is an equal and opposite
reaction."
>> If this means "instantly," then clearly there is a flaw. Does this mean
>> that Newton is wrong, or merely incomplete?
>>
>> Since we routinely use Newton to chart the heavens, launch satellites
>> etc. etc., it is clear that Newton isn't WRONG. I believe the answer is
>> "incomplete."
>>
>> Let's take your line of balls idea a step farther. First, let's assume
>> that the second ball is slightly out of line with all the others. When
we
>> strike the first ball, it p***** the impact on to the second ball
>> slightly off center. This acts to transfer some of the impact in a
>> straight line, but also causes it to rotate. This imparts angular
>> momentum to the second ball -- and subsequent balls. The reaction is
not
>> the same as the action!
> -----------------
> But, at the point of contact the forces are the same whether or not the
> impact is dead on. You give some direct force but you also have some
> spin-on both balls. You still have conservation of angular momentum. No
> problem with Newton there -just consider the forces as vectors. Newton
> obviously did .
> ---------
>
>>
>> Now let's assume that it has been a while since we have played with our
>> balls. (Sorry! I couldn't resist!) A thick coating of dust covers all
the
>> balls.
>>
>> We strike the first ball, and as the traveling wave progresses, it
shakes
>> the dust off of all the other balls. This reduces the mass of each
ball.
>> Again, the reaction is not the same as the action.
>>
>> So... if Newton is incomplete, as it seems to be, then we need to
modify
>> the rules/formulae. The modification must accomodate retardation, deal
>> with changes in angular momentum, and handle situations where the
>> starting and ending m***** are not the same!
>>
>> These issues are im****tant in planetary systems. There, we have
distances
>> that are large WRT the speed of gravity, we have bodies that possess
>> angular momentum, and (like a comet whose mass changes as it travels
by)
>> bodies whose mass is not constant with time.
> ------
> But then considering only the first dusty ball, the problem becomes not
a
> two body problem but a multibody problem. Considering all the balls,
this
> is compounded. The failure is not Newton but in our ability to actually
> solve the resultant multibody problem. We don't know the m***** or
> velocities of the dust particles but they aren't being converted to
> energy so there is no change in the total system mass. You can still
> assume total momentum, angular and linear is unchanged- even if the
final
> interaction occurs some time later than the first collision.
>
> --
>
> Don Kelly dhky@[EMAIL PROTECTED]
> remove the X to answer
>
>
> ------------
>
>>
>> A gravitostatic model does not work in a gravitodynamic environment.
>>
>>> In the vacuum, we really do not know the propagation method
>>
>> True
>>
>>>and there are various proposed mechanisms including aether and virtual
>>>phonons and the delay depends on the velocity of light. (or gravity --
>>>they are not necessarily the same, although they SEEM to be)
>>> These all appear to be attempts to cope with mechanical forces at
>>> distances by some essentially fully mechanical coupling. Why?
>>
>> Because we seem to be wor****ping at the shrine of St, Isaac rather than
>> looking -- as Heaviside did in 1893 (!) -- at the facts.
>>
>>> Do the delays make Newton's law of action/reaction invalid?
>>
>> Not invalid. Just incomplete.
>>
>> ..After all, this
>>> was developed without consideration of delays. Timo points out the
>>> Heaviside view-all reactions are local. -
>>
>> True! But all actions are not!
>>
>> Bill
>>
>>> Don Kelly dhky@[EMAIL PROTECTED]
>>> remove the X to answer
>>>
Don & Spaceman
Don's ball exercise was an excellent ANALOGY but it does not represent an
EXAMPLE of the issues that I raised. I will cheerfully concede that the
dynamics of balls clicking together represents known (almost high-school
level) interactions between materials whose proprties are (or can be) well
known..
What is of interest to me is what happens when these "balls" are in space
and their only interaction is via gravity. In this case, we have to resort
to the concept of force fields.
(Please! let us not re-open the silly discussion about the "reality" of
fields.)
In my example, we have two m***** separated by a distance. We wiggle one
mass. MUCH later the effect is felt by the other mass. During that time
perid, the law of action and reaction does not hold.
There are other examples:
If one calculates the forces between a charged particle moving on the x
axis
and a particle moving along the z axis, we find the forces are unequal. (
Breitenburger "Magnetic Interaction betwen Charged Particles" A J Ph. 36,
505-515 1968 & Scanio, "Conservation of Momentum in electrodynamics... " A
J
Ph. 43, 258-260, 1975)
Also, if a charge moves past a magnetic dipole, the forces are unequal.
(****tis, "Electromagnetic Fields, Sources and Media" John Wiley & Sons
1978, pp 390-392)
There are others. See Ch 4 of Jefimenko's "Causality..." book for some
more.
This is not surprising. Newton's theory of gravitation is based on the
Gravitational Force Law, F = G(M1M2)/r sq.
This is a STATICS law. There is no provision for time dependency, whether
it
be location, velocity (linear or otherwise) nor of mass. Also, like
Coulomb,
it has an obvious flaw in that it "blows up" as
r --> 0. Or do we just "normalize" this away as some would have us do
with
Coulomb?
We do not (slavishly) attempt to apply Coulomb's Law to Electrodynamic
situations. Why should we do so with Newton?
Let's douse the candles and incense at Isaac's shrine and recognize that
his
is a great theory, or "law" if you wish..
It is incomplete.
Bill
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