On 16-Sept-24 3:01 pm, Luigi Fortunati wrote:

I realize the enormity of the title of this article that refutes a law
that is more than three centuries old and that has never been contested
until now, but before presenting this work, I have carefully checked
all the concepts, numbers and formulas and I am ready to present this
article of mine in all other possible venues if it is rejected by
Physics Review.

The only way to refute a theory without the use of experimental evidence
is to show that it is internally inconsistent.

Since you have provided neither experimental evidence nor a
demonstration of an internal inconsistency, what you've presented is not
a refutation.

Sylvia.

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Luigi Fortunati il 15/09/2024 19:01:35 ha scritto:

[[Mod. note -- Combining (4), (5), (6), (7), and (8), we have that
F_horse_right > F_horse_left (this is just (6) again)
= F_rope_right (by (8))

F_rope_left (by (5))

= F_stone_right (by (7))

F_stone_left (by (4)

This alternation of greater and equal cannot be correct because where
there is "greater" it means that there are net forces (and
accelerations) and where there is "equal" there are not.

Those formulas are for situation where there is acceleration and
therefore net forces. The equalities only apply to forces from the
ends of the same interaction. The force at on the horse side end of
the rope must be equal to the froce on the rope side end of the horse
because there is no mass between the horse and the rope. Likewise
there is no mass between the rope and the stone.

The three bodies move as a single body and, therefore, nowhere can
there be areas (small or large) that accelerate together with areas
that do not accelerate.

They do not move like a single rigid body. In particular, there are areas
of the horse that do not accelerate (hoofs when they touch the ground) and areas that do accelerate (hoofs when they don't touch the ground). When
the force in the rope vaires the length of the rope varies so the
accleretions at the two ends of the rope differ.

[[Mod. note -- In my analysis I idealized the rope as non-stretching,
so that the stone, rope, and non-hoof parts of the horse all share
a common acceleration. -- jt]]

[[Mod. note -- *If* we approximate the rope as having zero mass, then
(2) (F_rope_right - F_rope_left = m_rope a)
says that
the rope tension is the same at both ends, i.e.,
F_rope_right = F_rope_left. (9)

No! If the mass decreases, (2) says something else.

The accleration of the rope is roughly constant and fully determined
by the acclereations of the horse and stone. Therefore, wen the mass
decreaces so does the difference of F_rope_right and F_rope_left. The difference is zero if the mass of the rope is zero, regardless of
acceleration.

...

Newton also says: If some body, colliding with another body, will in
some way have changed with its force the motion of the other, in turn,
due to the opposing force, will undergo an equal change in its own
motion in the opposite direction.

[[Mod. note -- This statement is a bit ambiguous: I can't tell what
you mean by "motion". Are you referring to velocity? Acceleration?
Force? Linear momentum? Angular momentum?
-- jt]]

This sentence is not mine, it is Newton's and you can find it in his
book "Principles of natural philosophy" under "law III".

It isn't Newton's as Newton wrote his "Principia" in Latin. It isn't
Motte's, either, but uses the word "motion" in the same sense. The
full term is "quantity of motion" but Motte uses plain "motion" as a
shorter term for the product of mass and speed. In today's English the
usual word is "momentum".

He means to say (I think) that: "the collision of body A determines a variation of the linear motion of body B equal to the variation of the
linear motion of body A in the opposite direction".

Instead of "variation" Motte uses "change". Newton's focus is on initial
and final states although conservation of momFentum also apply during
the collision.

--
Mikko

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On 12/2/24 2:10 AM, Luigi Fortunati wrote:

I am not the first to say that Newton's third law is wrong.

Hmmm. Your arguments are all wrong, because you keep omitting important effects. (You have repetitively posted so many invalid arguments that
many/most participants around here simply ignore your posts.)

Einstein said it before me (implicitly), with his General Relativity.

No, he did not. Your notions about GR are seriously wrong.

With my animation https://www.geogebra.org/m/v33hu4en I show what
Newton said.

I never click on such links.

[...]
Instead, Einstein argues that there is no force between the particles
of the Earth and those of the Moon, and that the action between the two bodies is due to the space-time curvature of one in contrast to the
different space-time curvature of the other.

That is not correct. Using the spacetime curvature interpretation of GR,
it is the curvature due to ALL components of the solar system that
determines all of their orbits. It is possible to only APPROXIMATELY
separate it as you assume, and that approximation destroys your argument.

But the two curvatures are not equal!

Of course not! Granting your separation, their effects are not equal,
either. The effect of earth on moon is huge and causes the moon to orbit
around the earth. The effect of moon on earth is MUCH smaller, and
merely makes it wiggle a little bit as it orbits the sun.

Consider a solar system with just sun, earth, and moon (i.e. ignore
everything else). The earth does not orbit around an ellipse, not even approximately -- it is the earth-moon barycenter that orbits around the (approximate) ellipse you are thinking of. The earth wiggles around that (approximate) ellipse. The wiggles have period ~ 29.5 days,
corresponding to the moon's orbit. (This is exact in Newtonian
mechanics, but only approximate in GR -- NM is linear while GR is not.)

And therefore, even for Einstein, the gravitational equality between
the two opposing bodies no longer exists, ]...]

Hmmm. Newton's third law discusses FORCES, not "gravitational equality".
In Newtonian mechanics, because earth and moon have such different
masses, the effects of equal forces on them are most definitely NOT
equal. In the spacetime curvature interpretation of GR there are no gravitational forces, and one simply cannot apply any of Newton's laws.
(But one can apply the Newtonian approximation to GR, and all three of
Newton's laws apply within that approximation.)

Hint: it is outrageously arrogant to think you alone can see an error in
a theory that has stood the test of time for hundreds of years and
inspection by tens of thousands of physicists. There is a reason that no journal articles have been published on this....

Tom Roberts

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On 12/16/24 4:24 AM, Luigi Fortunati wrote:

Tom Roberts il 12/12/2024 09:20:30 ha scritto:

With my animation https://www.geogebra.org/m/v33hu4en I show what
Newton said.

I never click on such links.

My Geogebra works are the heart of my proofs and thought experiments.
And you make your judgments without even looking at them.

But your statements here show a major lack of understanding, and invalid attempts to intermix Newtonian mechanics and General Relativity.

[...]
Instead, Einstein argues that there is no force between the particles
of the Earth and those of the Moon, and that the action between the two
bodies is due to the space-time curvature of one in contrast to the
different space-time curvature of the other.

That is not correct. Using the spacetime curvature interpretation of GR,
it is the curvature due to ALL components of the solar system that
determines all of their orbits.

What do the curvatures due to all the other components of the solar
system have to do with it?
And while you're at it, why don't you add all the other galaxies in the universe?

Yes, in principle one should do that. In practice their effects are
completely negligible.

The Earth's effect on the Moon is *much* larger than the Moon's effect
on the Earth because Earth's spacetime (which is more curved than the
Moon's) acts on the Moon *more* than the Moon's reacts on the Earth.

Hmmm. To claim that you must assume separation. But as I have said
several times before, GR is not separable like that. Removing the earth
from consideration affects the moon's path enormously; removing the moon affects the earth's path by only a small amount.

[...]
Hmmm. Newton's third law discusses FORCES, not "gravitational equality".

No, Newton's third law talks about "action and reaction" and not just
forces.

But TO NEWTON, "action and reaction" here refer to forces, not some
nebulous and undefined notion of yours. Your arguments here are based on
PUNs. (Nomenclature has changed over 300 years, and translation from
Latin adds additional ambiguity and potential for confusion.)

[...]
The third law can (and should) be applied in General Relativity because
it does not speak of forces but of action and reaction.

Strictly speaking, GR does not use forces to model gravitational
interactions -- it uses geometry [#]. But see above for the PUNs you use
here, which destroy your claims.

[#] in the geometrical interpretation of GR, which we are using.

The spacetime of General Relativity (with its curvature) acts between
the Earth and the Moon as the tension in Newton's string acts between
the horse and the stone.

That is not how GR actually models this. Geometry (spacetime) does not
"act", it just is. Moreover, GR is not separable, as you implicitly
assume here.

GR uses very different concepts from Newtonian mechanics. But you keep attempting to use Newtonian concepts to "describe" GR -- that's invalid.

[...]
I don't think I can see a mistake, I *prove* that the mistake is there
(for those who watch my animations).
An error that neither you nor anyone else have been able to detect.

Because there is no error, except by you.

I repeat: it is outrageously arrogant to think that you alone can see an
error in a theory that has stood the test of time for hundreds of years
and inspection by tens of thousands of physicists. As I have said
before, you REALLY need to take a course in physics at a college or university....

Tom Roberts

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