Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > sci.physics.relativity > #428849 > unrolled thread

Meditations about the force

Back to article view | Back to sci.physics.relativity

Contents

  Meditations about the force Luigi Fortunati <fortunati.luigi@gmail.com> - 2017-08-15 17:50 +0200
    Re: Meditations about the force Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-08-16 01:34 +0200
      Re: Meditations about the force mlwozniak@wp.pl - 2017-08-15 23:34 -0700
        Re: Meditations about the force Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-08-19 12:52 +0200
          Re: Meditations about the force Séverin Thibault <ruud@bwiu.ei> - 2017-08-19 11:04 +0000
          Re: Meditations about the force mlwozniak@wp.pl - 2017-08-19 10:43 -0700
      Re: Meditations about the force Luigi Fortunati <fortunati.luigi@gmail.com> - 2017-08-18 10:10 +0200
        Re: Meditations about the force mlwozniak@wp.pl - 2017-08-18 01:32 -0700
        Re: Meditations about the force Dirk Van de moortel <dirkvandemoortel@hotspam.not> - 2017-08-18 15:06 +0200
        Re: Meditations about the force Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-08-18 15:56 +0200
          Re: Meditations about the force mlwozniak@wp.pl - 2017-08-18 07:06 -0700
        Re: Meditations about the force "Paul B. Andersen" <relativity@paulba.no> - 2017-08-19 14:00 +0200
          Re: Meditations about the force Luigi Fortunati <fortunati.luigi@gmail.com> - 2017-08-19 17:45 +0200
            Re: Meditations about the force Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2017-08-19 21:28 +0200
          Re: Meditations about the force mlwozniak@wp.pl - 2017-08-19 10:44 -0700
          Re: Meditations about the force Thomas Heger <ttt_heg@web.de> - 2017-08-19 20:19 +0200
            Re: Meditations about the force Séverin Thibault <ruud@bwiu.ei> - 2017-08-19 19:56 +0000
              Re: Meditations about the force Séverin Thibault <ruud@bwiu.ei> - 2017-08-19 20:00 +0000

#428849 — Meditations about the force

The force of the wind pushes me forward, then I run and the wind is 
gone, it disappears along with its force.

If I have the same speed, the wind no longer exercises (it can not 
exert) any force on me.

In the river its water pushes me (it exerts a force on me) but if I (at 
dead body) then drift over the water, I do not feel any more push, the 
force the river exerted on me has vanished.

Third example: if I use my force to push the car I can do it until it 
has a speed equal to or greater than mine, then I can no longer exert 
any force on it because it no longer opposes me.

At that point I could be the strongest man in the world but my force is 
no longer manifest, it does not exist.

Fourth example, Einstein's bleacher.

As long as it is fixed on the scaffold, the force of gravity is there 
but when the bleacher falls (and no longer opposes resistance) the 
"force" of gravity disappears.

From the previous examples, is it fair to say that force is manifested 
exclusively when there is a resistance that opposes and never when 
every form of resistance is lacking?

-- 
Luigi Fortunati

Credere e' piu' facile che pensare
Believing is easier than thinking

[toc] | [next] | [standalone]

#428906

Luigi Fortunati wrote:

> From the previous examples, is it fair to say that force is manifested
> exclusively when there is a resistance that opposes and never when
> every form of resistance is lacking?

In the classical sense: Yes.  Other “forces” are only apparent forces.

For example (as we are in .relativity), general relativity postulates that 
the gravitational force (short: gravity) is an illusion, only an *apparent* 
force, too:

A body only "feels" its own weight due to gravity because there is a real 
force in the opposite direction, the repulsive electromagnetic force between 
the equally charged particles of matter (and because of the Pauli exclusion 
principle in more extreme cases), that *prevents* that body from continuing 
its motion along a spacetime geodesic.  If that resistance disappears, so do 
all effects of weight (weightlessness).

Einstein realized this in ca. 1911 when he considered a person in an 
elevator (“elevator experiment”): One in an elevator that is falling freely 
in a gravitational field, compared to one in an elevator that is far away 
from any source of gravity.  Likewise, a person in an elevator at rest in a 
gravitational field compared to a person in an "upwards" accelerated 
elevator far away from any source of gravity.  He realized that these two 
situations are physically equivalent, respectively: there is no experiment 
with which the person in the elevator can tell the difference.

<http://www.einstein-online.info/spotlights/equivalence_principle>

(It took him 5 more years to work out the complex mathematics to describe 
this properly: the [Einstein] field equations [EFEs].)

Prof. Brian Greene gives an excellent made-for-laymen summary and 
demonstration of this in “The Late Show with Stephen Colbert”:

<https://www.youtube.com/watch?v=0jjFjC30-4A>
 
-- 
PointedEars

Twitter: @PointedEars2
Please do not cc me. / Bitte keine Kopien per E-Mail.

[toc] | [prev] | [next] | [standalone]

#428959

W dniu środa, 16 sierpnia 2017 01:34:24 UTC+2 użytkownik Thomas 'PointedEars' 
> 
> Einstein realized this in ca. 1911 when he considered a person in an 
> elevator (“elevator experiment”)

A lie, as expected from fanatic trash. Einstein imagined
and there was no experiment.

[toc] | [prev] | [next] | [standalone]

#429376

mlwozniak@wp.pl wrote:

> W dniu środa, 16 sierpnia 2017 01:34:24 UTC+2 użytkownik Thomas
> 'PointedEars'
>> Einstein realized this in ca. 1911 when he considered a person in an
>> elevator (“elevator experiment”)
> 
> A lie, as expected from fanatic trash. Einstein imagined
> and there was no experiment.

The idea came to him while he was riding in an elevator.

He then used his mind to think about what would happen under different 
circumstances, a thing that you are manifestly unable to do as you are 
brain-dead stupid.

Fuck off, gibbering idiot.

-- 
PointedEars

Twitter: @PointedEars2
Please do not cc me. / Bitte keine Kopien per E-Mail.

[toc] | [prev] | [next] | [standalone]

#429377

Thomas 'PointedEars' Lahn wrote:

>> W dniu środa, 16 sierpnia 2017 01:34:24 UTC+2 użytkownik Thomas
>> 'PointedEars'
>>> Einstein realized this in ca. 1911 when he considered a person in an
>>> elevator (“elevator experiment”)
>> 
>> A lie, as expected from fanatic trash. Einstein imagined and there was
>> no experiment.
> 
> The idea came to him while he was riding in an elevator.

How stupid can you be, there is no room for a horse in an elevator. Your 
country doesn't even have elevators, or such advancements in science and 
technology, to begin with.
*	_P	L	O	N	K_	*

[toc] | [prev] | [next] | [standalone]

#429437

W dniu sobota, 19 sierpnia 2017 12:52:08 UTC+2 użytkownik Thomas 'PointedEars' Lahn napisał:
> mlwozniak@wp.pl wrote:
> 
> > W dniu środa, 16 sierpnia 2017 01:34:24 UTC+2 użytkownik Thomas
> > 'PointedEars'
> >> Einstein realized this in ca. 1911 when he considered a person in an
> >> elevator (“elevator experiment”)
> > 
> > A lie, as expected from fanatic trash. Einstein imagined
> > and there was no experiment.
> 
> The idea came to him while he was riding in an elevator.
> He then used his mind to think about what would happen under different 
> circumstances, 

and now poor brainwashed morons like you are lying that
he realized and his delusions are experimentally confirmed.

[toc] | [prev] | [next] | [standalone]

#429231

Thomas 'PointedEars' Lahn alle ore 01:34:19 del 16/08/2017 ha scritto:
> For example (as we are in .relativity), general relativity postulates that 
> the gravitational force (short: gravity) is an illusion, only an *apparent* 
> force, too:

It is a controversial postulate.

What is the apparent force? It's an illusion! The apparent force 
"seems" to be there but it is not there.

And how does one distinguish a force from a force that is not there? 
You control the acceleration!

If there is acceleration the force is real (F=ma) if there is no 
acceleration the force is apparent, it is an illusion, it is a ghost.

A ball that rolls without friction seems to advance as though it were 
pushed by a force but there is no force, then?

Then there is no force because the ball moves but does not accelerate!

The inertia force is illusory (it is apparent) because it does not 
accelerate.

Instead gravity accelerates and is therefore real and not apparent.

Can you give me an example in which gravity is not associated with any 
acceleration?

-- 
Luigi Fortunati

Credere e' piu' facile che pensare
Believing is easier than thinking

[toc] | [prev] | [next] | [standalone]

#429232

W dniu piątek, 18 sierpnia 2017 10:10:42 UTC+2 użytkownik Luigi Fortunati napisał:
> Thomas 'PointedEars' Lahn alle ore 01:34:19 del 16/08/2017 ha scritto:
> > For example (as we are in .relativity), general relativity postulates that 
> > the gravitational force (short: gravity) is an illusion, only an *apparent* 
> > force, too:
> 
> It is a controversial postulate.

It's a mumble of an insane crazie. It means nothing.

[toc] | [prev] | [next] | [standalone]

#429244

Op 18-aug-2017 om 10:10 schreef Luigi Fortunati:
> Thomas 'PointedEars' Lahn alle ore 01:34:19 del 16/08/2017 ha scritto:
>> For example (as we are in .relativity), general relativity postulates
>> that the gravitational force (short: gravity) is an illusion, only an
>> *apparent* force, too:
>
> It is a controversial postulate.
>
> What is the apparent force? It's an illusion! The apparent force "seems"
> to be there but it is not there.
>
> And how does one distinguish a force from a force that is not there? You
> control the acceleration!
>
> If there is acceleration the force is real (F=ma) if there is no
> acceleration the force is apparent, it is an illusion, it is a ghost.
>
> A ball that rolls without friction seems to advance as though it were
> pushed by a force but there is no force, then?
>
> Then there is no force because the ball moves but does not accelerate!
>
> The inertia force is illusory (it is apparent) because it does not
> accelerate.
>
> Instead gravity accelerates and is therefore real and not apparent.
>
> Can you give me an example in which gravity is not associated with any
> acceleration?

A stranded whale on the beach, getting crushed by its
own weight -- dying.

Dirk Vdm

[toc] | [prev] | [next] | [standalone]

#429247

Luigi Fortunati wrote:

> Thomas 'PointedEars' Lahn alle ore 01:34:19 del 16/08/2017 ha scritto:
>> For example (as we are in .relativity), general relativity postulates
>> that the gravitational force (short: gravity) is an illusion, only an
>> *apparent* force, too:
> 
> It is a controversial postulate.

Maybe in past science, or outside of science.  In current science it is not 
controversial at all, given the number of experiments that confirm(ed) it.

There is one particular experiment that confirms it that is performed 
continuously – do you know what it is?
 
> What is the apparent force? It's an illusion!

Correct, except you need to say “an” instead of “the”.  There is not just 
one apparent force.

> The apparent force "seems" to be there but it is not there.

That is what *I* said.

> And how does one distinguish a force from a force that is not there?

I have already told you.

> You control the acceleration!

That statement does not make sense.
 
> If there is acceleration the force is real (F=ma) if there is no
> acceleration the force is apparent, it is an illusion, it is a ghost.
> 
> A ball that rolls without friction seems to advance as though it were
> pushed by a force but there is no force, then?

It is the classical, Aristotelian fallacy that a force would be necessary to 
keep things in motion:

<https://www.youtube.com/watch?v=mYDrufxpW9E>

Newton’s first law of motion already shows that to be false: “A body remains 
at rest or in inertial motion *unless* a force is acting upon it.”

This holds true even in general relativity, but one must redefine inertial 
motion as inertial motion along a spacetime geodesic.

> Then there is no force because the ball moves but does not accelerate!
> 
> The inertia force is illusory (it is apparent) because it does not
> accelerate.

You are contradicting yourself by saying nonsensical things after you said 
right, trivial things just after you have said the opposite, patently wrong 
things.
 
> Instead gravity accelerates and is therefore real and not apparent.

Not in general relativity, where spacetime is dynamic and is curved in the 
presence of energy–momentum.

That general relativity is not just a fancy idea, but corresponds well with 
observation, has been confirmed numerous times and is going to be confirmed 
again, and with even greater precision we hope, during this year’s total 
solar eclipse, on 2017-08-21 UTC.  Watch that space.
 
> Can you give me an example in which gravity is not associated with any
> acceleration?

Ex falso quodlibet.  You are proceeding from the (false) assumption that 
gravity is a real force in the first place.  Of course, *only* if you assume 
that it is a real force, then there has to be a corresponding real 
acceleration.

You must realize that a flat spacetime (or absolute space and time, as 
Newton thought) requires an attractive force – gravity – and acceleration, 
to have orbits; while a curved spacetime requires force and acceleration to 
be *absent* to have the same orbits.  In a curved mathematical space, the 
projection of the shortest path connecting two points is _not_ a line.  Try 
city-to-city flights on Terra for a start.

It also turns out that Newton’s idea of the gravitational force is only a 
good approximation as long as masses are small; IOW, the greater the masses, 
and speeds the greater the error in calculations based on Newtonian gravity:

The precession of the perihelion of Mercury cannot be explained using 
Newtonian gravity.  It can be explained with great precision using general 
relativity.

According to Newton, the stars’ light should have been deflected half as 
much by Sol than it was measured during the 1919 solar eclipse and later; 
put simply, they should have appeared somewhere else than observed.  They 
were observed almost exactly where general relativity predicted them to be.

<https://en.wikipedia.org/wiki/Tests_of_general_relativity>

Finally, according to Newton, those gravitational waves could never have 
been detected by LIGO as they have been, because in his view gravity 
propagated instantaneously.  They (GW150914) were detected exactly as 
general relativity predicted.  And again the second (GW151226) and third 
time (GW170104).

<https://en.wikipedia.org/wiki/List_of_gravitational_wave_observations>

If you do not want to discuss about the theories of relativity, you should 
not post here, in sci.physics.*relativity*.
 
-- 
PointedEars

Twitter: @PointedEars2
Please do not cc me. / Bitte keine Kopien per E-Mail.

[toc] | [prev] | [next] | [standalone]

#429252

W dniu piątek, 18 sierpnia 2017 15:56:39 UTC+2 użytkownik Thomas 'PointedEars' Lahn napisał:
> Luigi Fortunati wrote:
> 
> > Thomas 'PointedEars' Lahn alle ore 01:34:19 del 16/08/2017 ha scritto:
> >> For example (as we are in .relativity), general relativity postulates
> >> that the gravitational force (short: gravity) is an illusion, only an
> >> *apparent* force, too:
> > 
> > It is a controversial postulate.
> 
> Maybe in past science, or outside of science.  In current science it is not 
> controversial at all, given the number of experiments that confirm(ed) it.

Communists has a lot of experiments confirming the advantages
of communism, too. 
But at least they were not impudent enough to redefine "confirm"
especially for proving their shit is "confirmed".

[toc] | [prev] | [next] | [standalone]

#429386

Den 18.08.2017 10.10, skrev Luigi Fortunati:
> Thomas 'PointedEars' Lahn alle ore 01:34:19 del 16/08/2017 ha scritto:
>> For example (as we are in .relativity), general relativity postulates 
>> that the gravitational force (short: gravity) is an illusion, only an 
>> *apparent* force, too:
> 
> It is a controversial postulate.
> 
> What is the apparent force? It's an illusion! The apparent force "seems" 
> to be there but it is not there.
> 
> And how does one distinguish a force from a force that is not there? You 
> control the acceleration!
> 
> If there is acceleration the force is real (F=ma) if there is no 
> acceleration the force is apparent, it is an illusion, it is a ghost.
> 
> A ball that rolls without friction seems to advance as though it were 
> pushed by a force but there is no force, then?
> 
> Then there is no force because the ball moves but does not accelerate!
> 
> The inertia force is illusory (it is apparent) because it does not 
> accelerate.
> 
> Instead gravity accelerates and is therefore real and not apparent.
> 
> Can you give me an example in which gravity is not associated with any 
> acceleration?
> 

Acceleration is what an accelerometer measures.
When you are stationary on the ground, the accelerometer
says you are accelerating vertically upwards at 9.8 m/s.
In free fall, the accelerometer shows that your acceleration is zero.

The only thing that can accelerate you, is a real force
that is acting on you. When you are sitting on a chair,
there is a real force pushing your butt. This force is
measurable, and you can feel it. You are accelerating
according to F = mg. F can easily be measured with a scale.
In free fall, no force is acting on you, so you are
not accelerating.

-- 
Paul

https://paulba.no/

[toc] | [prev] | [next] | [standalone]

#429410

Paul B. Andersen alle ore 14:00:31 del 19/08/2017 ha scritto:
> Acceleration is what an accelerometer measures.
> When you are stationary on the ground, the accelerometer
> says you are accelerating vertically upwards at 9.8 m/s.

It is 9.8 m/s^2 and not 9.8 m/ s.

> In free fall, the accelerometer shows that your acceleration is zero.
>
> The only thing that can accelerate you, is a real force
> that is acting on you. When you are sitting on a chair,
> there is a real force pushing your butt. This force is
> measurable, and you can feel it. You are accelerating
> according to F = mg. F can easily be measured with a scale.

You said it well: this "strength" is measurable!

Your accelerometer is nothing more than a dynamometer that measures 
forces and not acceleration!

So much so that both me and the chair I sit on are firm and do not 
accelerate.

Between us there is only the strength of the chair (pushing me upwards) 
and the strength of my reaction (pushing the chair down).

Or vice versa, which is the same (strength and reaction are 
interchangeable).

And this is the "strength" that the accelerometer measures.

> In free fall, no force is acting on you, so you are
> not accelerating.

It is obvious that in the free fall the accelerometer does not measure 
any strength because I do not force against anything (there is nothing 
against me) and because gravity does not force against me (even I 
oppose it) !

Opposition only occurs when I crash on the ground and then there is the 
force and the accelerometer is the measure!

Before that fatal moment, I can only know the acceleration by measuring 
the variation in the speed with which Earth approaches me.

-- 
Luigi Fortunati

Credere e' piu' facile che pensare
Believing is easier than thinking

[toc] | [prev] | [next] | [standalone]

#429454

Luigi Fortunati wrote:

> Paul B. Andersen alle ore 14:00:31 del 19/08/2017 ha scritto:
>> Acceleration is what an accelerometer measures.
>> When you are stationary on the ground, the accelerometer
>> says you are accelerating vertically upwards at 9.8 m/s.
> 
> It is 9.8 m/s^2 and not 9.8 m/ s.

Correct, and I am pretty sure that Paul knows that.
 
>> In free fall, the accelerometer shows that your acceleration is zero.
>>
>> The only thing that can accelerate you, is a real force
>> that is acting on you. When you are sitting on a chair,
>> there is a real force pushing your butt. This force is
>> measurable, and you can feel it. You are accelerating
>> according to F = mg. F can easily be measured with a scale.
> 
> You said it well: this "strength" is measurable!
> 
> Your accelerometer is nothing more than a dynamometer that measures
> forces and not acceleration!
> 
> So much so that both me and the chair I sit on are firm and do not
> accelerate.

Wrong, as you can observe that when putting both the chair and yourself on a 
scale, the scale shows something greater than zero.  But only if the chair 
and you are not in free fall.  In free fall, you are also not making a dent 
in the chair.

So there is an “upwards” (away from the center of mass of Terra) directed 
force that prevents everything from continuing to fall freely, and the scale 
allows you to measure it.  That force – the electromagnetic force – results 
from the fact that the everything beneath the scale, the scale itself, the 
chair, and you, consist of crystals and atoms, and crystals and atoms 
consist of particles (called ions, protons, and electrons, in order of 
decreasing size) whose electric charge has the same sign, and that therefore 
repel one another [or, in the quantum-mechanical model, as electrons and 
protons are fermions (half spin), the Pauli exclusion principle disallows 
two or more of them from having the same quantum numbers, so there is a
so-called “Fermi pressure” against bringing them closer together].

But given what you have written, I do not expect you to accept that.  You 
have already proven yourself to have a closed mindset, to be one of those 
wannabes who can never accept as physical reality what they cannot 
*intuitively* understand.  As if human intuition would be a suitable measure 
of what is possible in the universe.

It would be better if you just stopped wasting our precious free time and 
silently go away.  There is enough of you people posing (sic) here already.

-- 
PointedEars

Twitter: @PointedEars2
Please do not cc me. / Bitte keine Kopien per E-Mail.

[toc] | [prev] | [next] | [standalone]

#429438

W dniu sobota, 19 sierpnia 2017 14:00:34 UTC+2 użytkownik Paul B. Andersen napisał:
> Den 18.08.2017 10.10, skrev Luigi Fortunati:
> > Thomas 'PointedEars' Lahn alle ore 01:34:19 del 16/08/2017 ha scritto:
> >> For example (as we are in .relativity), general relativity postulates 
> >> that the gravitational force (short: gravity) is an illusion, only an 
> >> *apparent* force, too:
> > 
> > It is a controversial postulate.
> > 
> > What is the apparent force? It's an illusion! The apparent force "seems" 
> > to be there but it is not there.
> > 
> > And how does one distinguish a force from a force that is not there? You 
> > control the acceleration!
> > 
> > If there is acceleration the force is real (F=ma) if there is no 
> > acceleration the force is apparent, it is an illusion, it is a ghost.
> > 
> > A ball that rolls without friction seems to advance as though it were 
> > pushed by a force but there is no force, then?
> > 
> > Then there is no force because the ball moves but does not accelerate!
> > 
> > The inertia force is illusory (it is apparent) because it does not 
> > accelerate.
> > 
> > Instead gravity accelerates and is therefore real and not apparent.
> > 
> > Can you give me an example in which gravity is not associated with any 
> > acceleration?
> > 
> 
> Acceleration is what an accelerometer measures.

https://en.wikipedia.org/wiki/Acceleration
No, poor idiot. Acceleration is d^2x/dt^2.

[toc] | [prev] | [next] | [standalone]

#429446

Am 19.08.2017 um 14:00 schrieb Paul B. Andersen:

>> It is a controversial postulate.
>>
>> What is the apparent force? It's an illusion! The apparent force
>> "seems" to be there but it is not there.
>>
>> And how does one distinguish a force from a force that is not there?
>> You control the acceleration!
>>
>> If there is acceleration the force is real (F=ma) if there is no
>> acceleration the force is apparent, it is an illusion, it is a ghost.
>>
>> A ball that rolls without friction seems to advance as though it were
>> pushed by a force but there is no force, then?
>>
>> Then there is no force because the ball moves but does not accelerate!
>>
>> The inertia force is illusory (it is apparent) because it does not
>> accelerate.
>>
>> Instead gravity accelerates and is therefore real and not apparent.
>>
>> Can you give me an example in which gravity is not associated with any
>> acceleration?
>>
>
> Acceleration is what an accelerometer measures.

Well, acceleration is measured by an accelerometer.

But WTH do you want to say with such a statement?

You certainly see, that 'acceleration' cannot be explained/defined by 
using the term 'acceleration' - not even in combination with the term 
'-meter'.

In case you want to know, what that 'really' is (gravity, acceleration 
and so forth), you cannot refer to the effect (acceleration) in the 
attempt to explain this phenomenon.

This is similar to the question 'how long is a meter?'.

You cannot say 'a meter is a distance of the length of one meter'.

TH

[toc] | [prev] | [next] | [standalone]

#429460

Thomas Heger wrote:

> Am 19.08.2017 um 14:00 schrieb Paul B. Andersen:
>> Acceleration is what an accelerometer measures.
> 
> Well, acceleration is measured by an accelerometer.

Two flies with one smack. Accelerometers measures a FORCE. Basics things 
in industry. Amazing how these pretenders can be so wrong.

[toc] | [prev] | [next] | [standalone]

#429463

Séverin Thibault wrote:

> Thomas Heger wrote:
> 
>> Am 19.08.2017 um 14:00 schrieb Paul B. Andersen:
>>> Acceleration is what an accelerometer measures.
>> 
>> Well, acceleration is measured by an accelerometer.
> 
> Two flies with one smack. Accelerometers measures a FORCE. Basics things
> in industry. Amazing how these pretenders can be so wrong.

That I need to specify, these guys never see an Accelerometer from the 
inside. Accelerometers are incompetent in ANYTHING regarding Acceleration!!

[toc] | [prev] | [standalone]

Back to top | Article view | sci.physics.relativity

csiph-web