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What is mass?

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  What is mass? gilber34 <fafa@invalid.com> - 2015-09-23 11:02 -0500
    Re: What is mass? Poutnik <Poutnik4NNTP@gmail.com> - 2015-09-23 18:55 +0200
    Re: What is mass? Fabian Russell <root@localhost.localdomain> - 2015-09-23 16:59 +0000
      Re: What is mass? Poutnik <Poutnik4NNTP@gmail.com> - 2015-09-23 19:12 +0200
        Re: What is mass? Poutnik <Poutnik4NNTP@gmail.com> - 2015-09-23 19:17 +0200
        Re: What is mass? Fabian Russell <root@localhost.localdomain> - 2015-09-23 17:34 +0000
          Re: What is mass? Poutnik <poutnik4nntp@gmail.com> - 2015-09-23 20:35 +0200
            Re: What is mass? omnilobe@gmail.com - 2015-09-23 12:40 -0700
            Re: What is mass? Fabian Russell <root@localhost.localdomain> - 2015-09-23 21:44 +0000
              Re: What is mass? Poutnik <poutnik4nntp@gmail.com> - 2015-09-24 08:50 +0200
                Re: What is mass? "Y.Porat" <y.y.porat@gmail.com> - 2015-09-26 22:34 -0700
          Re: What is mass? Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-09-26 08:35 +0200
            Re: What is mass? Fabian Russell <root@localhost.localdomain> - 2015-09-26 12:35 +0000
              Re: What is mass? Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-09-26 15:37 +0200
                Re: What is mass? john <johnsefton288@gmail.com> - 2015-09-26 07:14 -0700
                  Re: What is mass? Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-09-26 16:17 +0200
            a-hem; m = F/a is also gOOd noTthaTguY <abu.kuanysh05@gmail.com> - 2015-09-26 17:16 -0700
              Re: a-hem; m = F/a is also gOOd Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-09-27 03:26 +0200
                top-posting is frpowned upon by certain advertizers ... just don't ask them, why not noTthaTguY <abu.kuanysh05@gmail.com> - 2015-09-27 15:53 -0700
                  What is mass (was: top-posting is frpowned upon by certain advertizers ... just don't ask them, why not) Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-09-28 17:05 +0200
                    a.k.a photonics -- thanks for the tip (pi dollars is gOOd noTthaTguY <abu.kuanysh05@gmail.com> - 2015-09-29 11:28 -0700
                      Re: a.k.a photonics -- thanks for the tip (pi dollars is gOOd Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-09-29 21:01 +0200
                        no skwares in the medium of space noTthaTguY <abu.kuanysh05@gmail.com> - 2015-09-29 19:29 -0700
      Re: What is mass? "Y.Porat" <y.y.porat@gmail.com> - 2015-09-23 23:07 -0700
    Re: What is mass? "nuny@bid.nes" <Alien8752@gmail.com> - 2015-09-23 14:01 -0700
      Re: What is mass? "Y.Porat" <y.y.porat@gmail.com> - 2015-09-27 23:40 -0700
    Re: What is mass? "reber g=emc^2" <herbertglazier0@gmail.com> - 2015-09-24 13:36 -0700
    Re: What is mass? Yousuf Khan <bbbl67@spammenot.yahoo.com> - 2015-09-28 02:13 -0400
      Re: What is mass? Mahipal <mahipal7638@gmail.com> - 2015-09-28 09:27 -0700
        Re: What is mass? Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-09-29 04:31 +0200
          Re: What is mass? "Y.Porat" <y.y.porat@gmail.com> - 2015-09-29 00:29 -0700
            Re: What is mass? Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-09-29 13:21 +0200
              Re: What is mass? Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-09-29 13:34 +0200
              Re: What is mass? "Y.Porat" <y.y.porat@gmail.com> - 2015-09-29 05:19 -0700
          Re: What is mass? Mahipal <mahipal7638@gmail.com> - 2015-09-29 05:40 -0700
            Re: What is mass? Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-09-29 15:11 +0200
              Re: What is mass? Mahipal <mahipal7638@gmail.com> - 2015-09-29 06:37 -0700
                Re: What is mass? Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-09-29 16:22 +0200
                  Re: What is mass? Mahipal <mahipal7638@gmail.com> - 2015-09-29 07:51 -0700
                    Re: What is mass? Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-09-29 18:45 +0200
                      Re: What is mass? Mahipal <mahipal7638@gmail.com> - 2015-09-29 11:06 -0700
                        Re: What is mass? Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2015-09-29 21:00 +0200
                          Re: What is mass? Mahipal <mahipal7638@gmail.com> - 2015-09-29 13:47 -0700
                            Re: What is mass? "Ma Hipple" <invalid@example.com> - 2015-09-30 07:20 -0700
                Re: What is mass? "Alan Smith" <invalid@example.com> - 2015-09-29 07:33 -0700
            Re: What is mass? "Y.Porat" <y.y.porat@gmail.com> - 2015-09-30 02:21 -0700
              Re: What is mass? Mahipal <mahipal7638@gmail.com> - 2015-10-04 19:11 -0700
                Re: What is mass? "Y.Porat" <y.y.porat@gmail.com> - 2015-10-05 00:39 -0700
                  Re: What is mass? noTthaTguY <abu.kuanysh05@gmail.com> - 2015-10-05 18:38 -0700
                    Re: What is mass? Mahipal <mahipal7638@gmail.com> - 2015-10-05 18:50 -0700
                      Re: What is mass? "Eric Smith" <invalid@example.com> - 2015-10-05 20:01 -0700
                        Re: What is mass? Mahipal <mahipal7638@gmail.com> - 2015-10-05 20:49 -0700
                      Re: What is mass? "Y.Porat" <y.y.porat@gmail.com> - 2015-10-06 03:18 -0700
                Re: What is mass? "Fred Smith" <invalid@example.com> - 2015-10-06 17:41 -0700
                  Re: What is mass? Mahipal <mahipal7638@gmail.com> - 2015-10-06 19:38 -0700
                    Re: What is mass? "Greg Smith" <invalid@example.com> - 2015-10-07 06:59 -0700
                      Re: What is mass? gilber34 <fafa@invalid.com> - 2015-10-07 09:03 -0500
                        Re: What is mass? "Hank Smith" <invalid@example.com> - 2015-10-07 07:20 -0700
                          Re: What is mass? Mahipal <mahipal7638@gmail.com> - 2015-10-07 08:11 -0700
                            Re: What is mass? noTthaTguY <abu.kuanysh05@gmail.com> - 2015-10-07 16:07 -0700
                              Re: What is mass? "Y.Porat" <y.y.porat@gmail.com> - 2015-10-08 00:18 -0700
                                Re: What is mass? john <johnsefton288@gmail.com> - 2015-10-08 06:15 -0700
                                  Re: What is mass? "Y.Porat" <y.y.porat@gmail.com> - 2015-10-10 01:11 -0700
                                    Re: What is mass? noTthaTguY <abu.kuanysh05@gmail.com> - 2015-10-10 16:43 -0700
                                Re: What is mass? noTthaTguY <abu.kuanysh05@gmail.com> - 2015-10-08 12:34 -0700

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#522840 — What is mass?

I now understand that mass is only defined by its effects, so I realize 
that my biggest problem is related to quantification. I don't understand 
how people came up with a system to quantify mass.

I tried to figure it out using the formula for mass, which is F= m . a 
and my issue was the following: a: Acceleration as a concept is very 
straightforward.

It's a measure of the distance in relation to the time in which it is 
traveled. In order to measure distance, we've taken an arbitrary amount 
of space and called it a meter and an arbitrary amount of time and 
called it seconds.

Nothing to look for there, it's all arbitrary. F: Same with force. In 
order to quantify it, we arbitrarily decided to equal 1 unit of force 
(newton) with what is needed to make an object of 1 kilogram have an 
acceleration of 1 meter per second. m:

But when it comes to mass, I don't see what they used to quantify it 
(given that it's definitely not the amount of atoms contained in an 
object). You could say that it's that which causes the needed force to 
accelerate the object to be greater the bigger it is, but then there's a 
loophole in the definition (force is defined in terms of mass and mass 
is defined in terms of force).

So what basis was used to standardize the measurement of the concept of 
mass?

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#522855

On 09/23/2015 06:02 PM, gilber34 wrote:

> 
> But when it comes to mass, I don't see what they used to quantify it 
> (given that it's definitely not the amount of atoms contained in an 
> object). You could say that it's that which causes the needed force to 
> accelerate the object to be greater the bigger it is, but then there's a 
> loophole in the definition (force is defined in terms of mass and mass 
> is defined in terms of force).
> 
> So what basis was used to standardize the measurement of the concept of 
> mass?
> 

The unit of mass 1 kg is for now defined
as the mass of the 1kg platinum-iridium etalone
stored in a metrology institure in Paris.

There is movement to redefine it via basic physical constants,
but the above is still valid.

The unit of force 1 N is then defined
as the force causing to 1 kg mass the acceleration 1 m/s^2


-- 
Poutnik ( the Czech word for a wanderer )

Knowledge makes a great man humble, but a small man arrogant.

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#522856

On Wed, 23 Sep 2015 11:02:59 -0500, gilber34 wrote:

> 
> I tried to figure it out using the formula for mass, which is F= m . a 
>

That equation is completely *wrong*, and, furthermore, it is an error
that is inexcusably propagated in all physics textbooks today.

The correct equation is: F = m_inertial * a.

There are two kinds of mass: inertial and gravitation.

Gravitational mass is defined by the equation: G * m_gravitational/r^2.

Although it is assumed that inertial mass equals gravitational mass,
m_inertial = m_gravitational, it has not ever been proven to be the
case.  The equality is the cornerstone of General Relativity (GR) and
it has been experimentally verified to high precision.  But verification
is not the same thing as a theoretical proof, although the validity
of GR implies its correctness.  (Keep in mind that GR still has competing
theories and is not absolutely established.)

 

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#522860

On 09/23/2015 06:59 PM, Fabian Russell wrote:
> On Wed, 23 Sep 2015 11:02:59 -0500, gilber34 wrote:
> 
>>
>> I tried to figure it out using the formula for mass, which is F= m . a 
>>
> 
> That equation is completely *wrong*, and, furthermore, it is an error
> that is inexcusably propagated in all physics textbooks today.

> 
> The correct equation is: F = m_inertial * a.
> 
> There are two kinds of mass: inertial and gravitation.
> 
> Gravitational mass is defined by the equation: G * m_gravitational/r^2.


Limit case of General relativity for flat space-time and v << c
cannot be completely wrong equation.


-- 
Poutnik ( the Czech word for a wanderer )

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#522862

On 09/23/2015 07:12 PM, Poutnik wrote:
> On 09/23/2015 06:59 PM, Fabian Russell wrote:
>> On Wed, 23 Sep 2015 11:02:59 -0500, gilber34 wrote:
>>
>>>
>>> I tried to figure it out using the formula for mass, which is F= m . a 
>>>
>>
>> That equation is completely *wrong*, and, furthermore, it is an error
>> that is inexcusably propagated in all physics textbooks today.
> 
>>
>> The correct equation is: F = m_inertial * a.
>>
>> There are two kinds of mass: inertial and gravitation.
>>
>> Gravitational mass is defined by the equation: G * m_gravitational/r^2.
> 
> 
> Limit case of General relativity for flat space-time and v << c
> cannot be completely wrong equation.
> 
> 
P.S.> Completely wrong equation would provide error
much bigger than is error caused by errors in determination
of values of force, mass or acceleration.

It is not the case.

-- 
Poutnik ( the Czech word for a wanderer )

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#522866

On Wed, 23 Sep 2015 19:12:18 +0200, Poutnik wrote:

> 
> cannot be completely wrong equation.
>

The equation is wrong because it specifies mass, m, as *the* mass,
i.e. the definitive mass or the one-and-only mass.

Correctly written, the *inertial* mass must be indicated because,
as already stated, there are two different "kinds" of mass.

For some reason, the concepts of inertial mass and gravitational
mass have been effectively purged from physics, but they are still
valid.  GR *assumes* the equivalence of both types and perhaps for
this reason all textbooks incorrectly mention only a single type
of mass.  But, as also mentioned, GR is not yet universally established.

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#522879

Dne 23/09/2015 v 19:34 Fabian Russell napsal(a):
> On Wed, 23 Sep 2015 19:12:18 +0200, Poutnik wrote:
> 
>>
>> cannot be completely wrong equation.
>>
> 
> The equation is wrong because it specifies mass, m, as *the* mass,
> i.e. the definitive mass or the one-and-only mass.
> 
> Correctly written, the *inertial* mass must be indicated because,
> as already stated, there are two different "kinds" of mass.

In fact not, as current interpretation of GR uses
the single, invariant mass.

Inertial mass is not invariant, is even direction dependent,
and is not used anymore in GR context.

> 
> For some reason, the concepts of inertial mass and gravitational
> mass have been effectively purged from physics, but they are still
> valid.  GR *assumes* the equivalence of both types and perhaps for
> this reason all textbooks incorrectly mention only a single type
> of mass.  But, as also mentioned, GR is not yet universally established.
> 
Eqaulity of inertial and gravitational mass
must be than equally completely wrong,
as it is limit case as well.

-- 
Poutnik ( the Czech word for a wanderer )

Knowledge makes great men humble, but small men arrogant.

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#522884

mass is area

1 kg = area of protons and neutrons plus adjacent continuum fluid area

1 kg = 1 square meter 

inertial force is f

f = 590n pi r^2 times acceleration

where r is proton radius 0.95 fm
n is number of protons and neutrons in Mass

the 590 is viscosity of continuum 4D fluid

See Folmsbee Gravity Theory
mass does not cause gravity, mass is affected by the gravitational gradient of continuum

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#522897

On Wed, 23 Sep 2015 20:35:26 +0200, Poutnik wrote:

> 
> In fact not, as current interpretation of GR uses
> the single, invariant mass.
> 

GR uses the stress-energy tensor as the invariant source of
the gravitational field.

But in general physics there should always be made the distinction
between inertial and gravitational mass.  Historically they were
not the same and technically they are not the same.

Gravitational mass defines the (Newtonian) gravitational potential
field:

V(r) = G * m_gravitational/r

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#522948

Dne 23/09/2015 v 23:44 Fabian Russell napsal(a):
> On Wed, 23 Sep 2015 20:35:26 +0200, Poutnik wrote:
> 
>>
>> In fact not, as current interpretation of GR uses
>> the single, invariant mass.
>>
> 
> GR uses the stress-energy tensor as the invariant source of
> the gravitational field.
> 
> But in general physics there should always be made the distinction
> between inertial and gravitational mass.  Historically they were
> not the same and technically they are not the same.
> 
> Gravitational mass defines the (Newtonian) gravitational potential
> field:
> 
> V(r) = G * m_gravitational/r
> 
With accuracy of G,
F = m.a is much more accurate formula for v << c.

-- 
Poutnik ( the Czech word for a wanderer )

Knowledge makes great men humble, but small men arrogant.

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#523395

On Thursday, September 24, 2015 at 9:50:54 AM UTC+3, Poutnik wrote:
> Dne 23/09/2015 v 23:44 Fabian Russell napsal(a):
> > On Wed, 23 Sep 2015 20:35:26 +0200, Poutnik wrote:
> > 
> >>
> >> In fact not, as current interpretation of GR uses
> >> the single, invariant mass.
> >>
> > 
> > GR uses the stress-energy tensor as the invariant source of
> > the gravitational field.
> > 
> > But in general physics there should always be made the distinction
> > between inertial and gravitational mass.  Historically they were
> > not the same and technically they are not the same.
> > 
> > Gravitational mass defines the (Newtonian) gravitational potential
> > field:
> > 
> > V(r) = G * m_gravitational/r
> > 
> With accuracy of G,
> F = m.a is much more accurate formula for v << c.
> 
> -- 
> Poutnik ( the Czech word for a wanderer )
> 
> Knowledge makes great men humble, but small men arrogant.

===========================
some news for you parrot :
for velocities closer to c 

F /Gamma = ma

AND m REMAINS CONSTANT !!
=============================================
NO MASS - **THE ONLY MASS - NO REAL PHYSICS !!
===============================================

Y.Porat
==============================

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#523242

[X-Post sci.physics, sci.physics.relativity;
 F'up2  <news:sci.physics.relativity>]

Fabian Russell wrote:

> On Wed, 23 Sep 2015 19:12:18 +0200, Poutnik wrote:
>> cannot be completely wrong equation.
> 
> The equation is wrong because it specifies mass, m, as *the* mass,
> i.e. the definitive mass or the one-and-only mass.

There is only mass.  To answer the question in the Subject header field 
value: Mass is a measure of the energy content of a body at rest in the 
laboratory frame (of reference): E = √(pc)² + (mc²)²) → m = E∕c² for p = 0, 
with p = γmv (relative rest → γ = 1, v = 0).

That is why we build huge machines to *accelerate* subatomar particles close 
to the speed of light in vacuum, and have them collide with each other to 
create particles with a lot of mass and, more recently, to "produce" energy 
through nuclear fusion.
 
> Correctly written, the *inertial* mass must be indicated because,
> as already stated, there are two different "kinds" of mass.

Two terms for the same thing is not how science works.
 
> For some reason, the concepts of inertial mass and gravitational
> mass have been effectively purged from physics,

Because physics is a science.  Superfluous terms are not used in science.  
One uses different terms for different things, the same term for the same 
thing.

> but they are still valid.

Because you say so?

> GR *assumes* the equivalence of both types

Because it can be *demonstrated*.  Read on the elevator experiment: Without 
additional information, you cannot tell whether you are far away from a 
source of gravity or in free fall, and you cannot tell whether you are 
accelerating or near a source of gravity.

(Einstein is often described as a theoretical genius only.  But, in fact, 
the text of his works shows that he was deeply guided by experiment.  And 
there is other evidence: He co-designed and had built an observatory [the 
Einsteinturm in Potsdam, Germany] only for testing GR.  And he would have 
thrown out GR like yesterday’s newspaper if it had given the wrong result 
for the precession of the perihelion of Mercury.  Just as he wrote [in 
German] “then away with the cosmological term” regarding his field equations 
when Hubble’s observations confirmed Lemaître’s theory that the universe was 
in fact not static, but expanding.)

> and perhaps for this reason all textbooks incorrectly mention only a 
> single type of mass.  But, as also mentioned, GR is not yet universally
> established.

In crackpot’s heads, perhaps.  Everywhere else it is, quite literally, 
“universally” established, for example:

- in timekeeping (precise clocks are gauged based on their elevation; it can
  be demonstrated that those at higher elevation tick faster than their
  same-model counterparts at lower elevation)

- in communication (with orbital spacecraft and interplanetary probes);

  * as a special case, in satellite navigation (GPS and alternatives)

  (again, clocks close to a massive body tick slower than those farther away
  from it)

- in astronomy and astrophysics (perihelion precession, gravitational
  lensing, black holes)

- in cosmology (the ΛCDM, or *standard* model of cosmology)


PointedEars
-- 
“Science is empirical: knowing the answer means nothing;
 testing your knowledge means everything.”
   —Dr. Lawrence M. Krauss, theoretical physicist,
    in “A Universe from Nothing” (2009)

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#523256

On Sat, 26 Sep 2015 08:35:23 +0200, Thomas 'PointedEars' Lahn wrote:

> 
> There is only mass.
> 
> Two terms for the same thing is not how science works.
>  

http://www.umich.edu/~mctp/SciPrgPgs/events/2008/SS08/EP_Mich.pdf\u200e

http://mek.oszk.hu/02000/02054/html/onehund.html

http://astronomy.swin.edu.au/sao/downloads/HET625-M04A01.pdf

Etc., etc., etc.

In other words, go and fuck yourself.

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#523259

Fabian Russell wrote:

> On Sat, 26 Sep 2015 08:35:23 +0200, Thomas 'PointedEars' Lahn wrote:
>> There is only mass.
>> 
>> Two terms for the same thing is not how science works.
> 
> http://www.umich.edu/~mctp/SciPrgPgs/events/2008/SS08/EP_Mich.pdf\u200e

404-compliant, and in 
<http://www.umich.edu/~mctp/SciPrgPgs/events/2008/SS08/EP_Mich.pdf> one can 
read in “Conclusions”:

| […]
| The EP [equivalence principle; the ed.] is one of the most precisely 
                                             ^^^^^^^^^^^^^^^^^^^^^^^^^
| tested principles in all of physics with many broad implications
  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
| […]
| No evidence yet for a breakdown of the EP.  For example: 
  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
| 
|   the weight of gravity agrees with Einstein’s prediction to
|     better than 1 part in 10³
      ^^^^^^^^^^^^^^^^^^^^^^^^^
|   assuming CPT symmetry, anti-H falls with the same
|     acceleration as H to within 2 parts in 10¹⁰
                                  ^^^^^^^^^^^^^^^
|   laboratory proof that gravity is the dominant long-range force between
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|     dark and luminous matter
      ^^^^^^^^^^^^^^^^^^^^^^^^

> http://mek.oszk.hu/02000/02054/html/onehund.html

| […] Baron Roland von Eötvös experimentally investigated the 
| proportionality of inertial and gravitating masses in 1889, and reported 
                                                        ^^^^
| his results in the Proceedings of the Hungarian Academy in 1890
                                                             ^^^^
vs.

<http://www-history.mcs.st-and.ac.uk/HistTopics/General_relativity.html>

| Immediately after Einstein's 1915 paper giving the correct field 
                               ^^^^                  ^^^^^^^^^^^^^
| equations, Karl Schwarzschild found in 1916 a mathematical solution to the 
  ^^^^^^^^^                              ^^^^
| equations which corresponds to the gravitational field of a massive 
                                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
| compact object. At the time this was purely theoretical work but, of 
  ^^^^^^^^^^^^^^^                                                   ^^
| course, work on neutron stars, pulsars and black holes relied entirely on 
  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
| Schwarzschild's solutions and has made this part of the most important 
  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
| work going on in astronomy today.
  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

> http://astronomy.swin.edu.au/sao/downloads/HET625-M04A01.pdf

| Summary
| 
| In this activity we looked at early experiments of gravity, two different 
                                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
| kinds of experiential masses (inertial and gravitational) and the 
| formulation of the Weak Equivalence Principal.
  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
| In the next activity we’re going to investigate gravity and acceleration 
| in quite a bit more detail. We’ll start by jumping in an elevator and
                                                           ^^^^^^^^
| going for a ride...
 
> Etc., etc., etc.

You mean all the other sources that you have not read carefully?

> In other words, go and fuck yourself.

Crackpot.  Q.E.D.


PointedEars
-- 
Q: What did the nuclear physicist order for lunch?  
A: Fission chips.

(from: WolframAlpha)

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#523260

The mass of the Earth varies according
to a sine wave- recently found to be
due to its 'wobble'

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#523261

john wrote:

> The mass of the Earth varies according
> to a sine wave- recently found to be
> due to its 'wobble'

Cite evidence.


PointedEars
-- 
“Science is empirical: knowing the answer means nothing;
 testing your knowledge means everything.”
   —Dr. Lawrence M. Krauss, theoretical physicist,
    in “A Universe from Nothing” (2009)

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#523332 — a-hem; m = F/a is also gOOd

thanks for the gOOd (longform equation (although
the standard about the secondpower of the speed
pf lightwaves is really cOOl, though
it is not in the most prosaical format

> There is only mass.  To answer the question in the Subject header field 
> value: Mass is a measure of the energy content of a body at rest in the 
> laboratory frame (of reference): E = √(pc)² + (mc²)²) → m = E∕c² for p = 0, 
> with p = γmv (relative rest → γ = 1, v = 0).
> 
> That is why we build huge machines to *accelerate* subatomar particles close 
> to the speed of light in vacuum, and have them collide with each other to 
> create particles with a lot of mass and, more recently, to "produce" energy 
> through nuclear fusion.
>  
> > Correctly written, the *inertial* mass must be indicated because,
> > as already stated, there are two different "kinds" of mass.
> 
> Two terms for the same thing is not how science works.
>  
> > For some reason, the concepts of inertial mass and gravitational
> > mass have been effectively purged from physics,
> 
> Because physics is a science.  Superfluous terms are not used in science.  
> One uses different terms for different things, the same term for the same 
> thing.
> 
> > but they are still valid.
> 
> Because you say so?
> 
> > GR *assumes* the equivalence of both types
> 
> Because it can be *demonstrated*.  Read on the elevator experiment: Without 
> additional information, you cannot tell whether you are far away from a 
> source of gravity or in free fall, and you cannot tell whether you are 
> accelerating or near a source of gravity.
> 
> (Einstein is often described as a theoretical genius only.  But, in fact, 
> the text of his works shows that he was deeply guided by experiment.  And 
> there is other evidence: He co-designed and had built an observatory [the 
> Einsteinturm in Potsdam, Germany] only for testing GR.  And he would have 
> thrown out GR like yesterday’s newspaper if it had given the wrong result 
> for the precession of the perihelion of Mercury.  Just as he wrote [in 
> German] “then away with the cosmological term” regarding his field equations 
> when Hubble’s observations confirmed Lemaître’s theory that the universe was 
> in fact not static, but expanding.)
> 
> > and perhaps for this reason all textbooks incorrectly mention only a 
> > single type of mass.  But, as also mentioned, GR is not yet universally
> > established.
> 
> In crackpot’s heads, perhaps.  Everywhere else it is, quite literally, 
> “universally” established, for example:
> 
> - in timekeeping (precise clocks are gauged based on their elevation; it can
>   be demonstrated that those at higher elevation tick faster than their
>   same-model counterparts at lower elevation)
> 
> - in communication (with orbital spacecraft and interplanetary probes);
> 
>   * as a special case, in satellite navigation (GPS and alternatives)
> 
>   (again, clocks close to a massive body tick slower than those farther away
>   from it)
> 
> - in astronomy and astrophysics (perihelion precession, gravitational
>   lensing, black holes)
> 
> - in cosmology (the ΛCDM, or *standard* model of cosmology)
> 
> 
> PointedEars
> -- 
> “Science is empirical: knowing the answer means nothing;
>  testing your knowledge means everything.”
>    —Dr. Lawrence M. Krauss, theoretical physicist,
>     in “A Universe from Nothing” (2009)

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#523363 — Re: a-hem; m = F/a is also gOOd

noTthaTguY wrote:
^^^^^^^^^^
Your real name belongs there.

[fixed quotation]

>> There is only mass.  To answer the question in the Subject header field
>> value: Mass is a measure of the energy content of a body at rest in the
>> laboratory frame (of reference): E = √(pc)² + (mc²)²) → m = E∕c² for p =
>> 0, with p = γmv (relative rest → γ = 1, v = 0).
>
> thanks for the gOOd (longform equation (although
> the standard about the secondpower of the speed
> pf lightwaves is really cOOl, though
> it is not in the most prosaical format

I forgot a leading “(” after the “√”.  Apart from that: Huh?

And please do not top-post.


PointedEars
-- 
Q: What happens when electrons lose their energy?  
A: They get Bohr'ed.

(from: WolframAlpha)

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#523508 — top-posting is frpowned upon by certain advertizers ... just don't ask them, why not

I will publish the somewhat more canonical version
of E/c = mc, later, but, you could guess

> >> laboratory frame (of reference): E = √((pc)² + (mc²)²) → m = E∕c² for p =
> >> 0, with p = γmv (relative rest → γ = 1, v = 0).
> >
> > the standard about the secondpower of the speed
> > of lightwaves is really cOOl, though
> > it is not in the most prosaical format
> 
> I forgot a leading “(” after the “√”.  Apart from that: Huh?
> 
> And please do not top-post.
> 
> 
> PointedEars
> -- 
> Q: What happens when electrons lose their energy?  
> A: They get Bohr'ed.
> 
> (from: WolframAlpha)

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#523571 — What is mass (was: top-posting is frpowned upon by certain advertizers ... just don't ask them, why not)

noTthaTguY wrote:

[restored minimum attribution]

> Thomas 'PointedEars' Lahn wrote:
>> >> laboratory frame (of reference): E = √((pc)² + (mc²)²) → m = E∕c² for
>> >> p = 0, with p = γmv (relative rest → γ = 1, v = 0).
>> >
>> > the standard about the secondpower of the speed
>> > of lightwaves is really cOOl, though
>> > it is not in the most prosaical format
>> 
>> I forgot a leading “(” after the “√”.  Apart from that: Huh?
>> 
>> And please do not top-post.
> 
> I will publish the somewhat more canonical version of E/c = mc,
                     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
How did you get that idea?

> later, but, you could guess

Guess what?

And as for the Subject header which has *again* been inappropriately changed 
by you: that is incredibly stupid.  I am not an advertiser; I am just not a 
bat, so I prefer to read text from top to bottom.  And so should you, and 
post accordingly.  As for posting with your real name: that would be simple 
politeness helping to tell you apart from trolls and cranks.


PointedEars
-- 
Q: What did the female magnet say to the male magnet?  
A: From the back, I found you repulsive, but from the front
   I find myself very attracted to you.
(from: WolframAlpha)

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