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the famous formula

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  the famous formula RichD <r_delaney2001@yahoo.com> - 2018-12-06 10:49 -0800
    Re: the famous formula pnalsing@gmail.com - 2018-12-06 11:30 -0800
    Re: the famous formula dlzc <dlzc1@cox.net> - 2018-12-06 11:43 -0800
      Re: the famous formula RichD <r_delaney2001@yahoo.com> - 2018-12-07 10:15 -0800
        Re: the famous formula dlzc <dlzc1@cox.net> - 2018-12-07 11:13 -0800
          Re: the famous formula RichD <r_delaney2001@yahoo.com> - 2018-12-09 00:02 -0800
            Re: the famous formula dlzc <dlzc1@cox.net> - 2018-12-09 15:23 -0800
              Re: the famous formula Libor Striz <poutnik@privacy.net> - 2018-12-10 09:54 +0100
                Re: the famous formula dlzc <dlzc1@cox.net> - 2018-12-10 05:43 -0800
                  Re: the famous formula Tom Roberts <tjroberts137@sbcglobal.net> - 2018-12-12 11:08 -0600
                    Re: the famous formula dlzc <dlzc1@cox.net> - 2018-12-12 09:35 -0800
                    Re: the famous formula Rich Carpenter <lcug@kigcohc.pa> - 2018-12-12 19:20 +0000
                      Re: the famous formula Tom Roberts <tjroberts137@sbcglobal.net> - 2018-12-12 19:28 -0600
                        Re: the famous formula Scott Richman <sunn@idhnonow.iv> - 2018-12-13 16:13 +0000
                    Re: the famous formula "David (Kronos Prime) Fuller" <fuller.david@hotmail.com> - 2018-12-14 04:56 -0800
                      Re: the famous formula "David (Kronos Prime) Fuller" <fuller.david@hotmail.com> - 2018-12-14 05:23 -0800
          Re: the famous formula Tom Roberts <tjroberts137@sbcglobal.net> - 2018-12-12 10:28 -0600
            Re: the famous formula dlzc <dlzc1@cox.net> - 2018-12-12 09:12 -0800
              Re: the famous formula Tom Roberts <tjroberts137@sbcglobal.net> - 2018-12-14 12:21 -0600
    Re: the famous formula Thomas Heger <ttt_heg@web.de> - 2018-12-06 20:50 +0100
      Re: the famous formula Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2018-12-06 22:47 +0100
        Re: the famous formula Thomas Heger <ttt_heg@web.de> - 2018-12-07 12:06 +0100
          Re: the famous formula Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2018-12-07 16:15 +0100
            Re: the famous formula Thomas Heger <ttt_heg@web.de> - 2018-12-08 14:18 +0100
              Re: the famous formula Odd Bodkin <bodkinodd@gmail.com> - 2018-12-08 13:43 +0000
                Re: the famous formula "David (Kronos Prime) Fuller" <fuller.david@hotmail.com> - 2018-12-08 06:01 -0800
                  Re: the famous formula Thomas Heger <ttt_heg@web.de> - 2018-12-08 18:18 +0100
                    Re: the famous formula Libor Striz <poutnik4REMOVEnntp@CAPITALSgmail.com.INVALID> - 2018-12-08 19:26 +0100
                      Re: the famous formula Thomas Heger <ttt_heg@web.de> - 2018-12-09 19:35 +0100
                        Re: the famous formula Libor Striz <poutnik4REMOVEnntp@CAPITALSgmail.com.INVALID> - 2018-12-09 20:24 +0100
                          Re: the famous formula Thomas Heger <ttt_heg@web.de> - 2018-12-10 18:48 +0100
                            Re: the famous formula Rich Carpenter <lcug@kigcohc.pa> - 2018-12-10 19:37 +0000
                            Re: the famous formula Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2018-12-10 22:27 +0100
                              Re: the famous formula Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2018-12-10 22:35 +0100
                              Re: the famous formula Thomas Heger <ttt_heg@web.de> - 2018-12-12 16:45 +0100
                                Re: the famous formula Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2018-12-13 17:21 +0100
                        Re: the famous formula Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2018-12-09 19:03 +0100
                        Re: the famous formula Libor Striz <poutnik4REMOVEnntp@CAPITALSgmail.com.INVALID> - 2018-12-09 20:37 +0100
                        Re: the famous formula Odd Bodkin <bodkinodd@gmail.com> - 2018-12-09 22:20 +0000
                          Re: the famous formula Thomas Heger <ttt_heg@web.de> - 2018-12-10 18:40 +0100
                            Re: the famous formula Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2018-12-10 21:59 +0100
                            Re: the famous formula Odd Bodkin <bodkinodd@gmail.com> - 2018-12-10 21:41 +0000
                              Re: the famous formula Thomas Heger <ttt_heg@web.de> - 2018-12-11 16:31 +0100
                                Re: the famous formula Odd Bodkin <bodkinodd@gmail.com> - 2018-12-11 18:24 +0000
                                  Re: the famous formula Thomas Heger <ttt_heg@web.de> - 2018-12-12 16:32 +0100
                                    Re: the famous formula Odd Bodkin <bodkinodd@gmail.com> - 2018-12-12 16:27 +0000
                                      Re: the famous formula Thomas Heger <ttt_heg@web.de> - 2018-12-14 15:13 +0100
                                        Re: the famous formula Odd Bodkin <bodkinodd@gmail.com> - 2018-12-14 14:28 +0000
                                          Re: the famous formula Thomas Heger <ttt_heg@web.de> - 2018-12-15 13:35 +0100
                                            Re: the famous formula Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2018-12-15 13:52 +0100
                                              Re: the famous formula Thomas Heger <ttt_heg@web.de> - 2018-12-15 19:50 +0100
                                                Re: the famous formula Odd Bodkin <bodkinodd@gmail.com> - 2018-12-15 20:33 +0000
                                                Re: the famous formula Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2018-12-15 22:02 +0100
                                            Re: the famous formula Odd Bodkin <bodkinodd@gmail.com> - 2018-12-15 12:55 +0000
                                    Re: the famous formula Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2018-12-13 23:14 +0100
                                [OT] Work (was: the famous formula) Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2018-12-11 21:56 +0100
                    Re: the famous formula Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2018-12-08 20:14 +0100
              Re: the famous formula Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2018-12-09 19:22 +0100
          Re: the famous formula Libor Striz <poutnik4REMOVEnntp@CAPITALSgmail.com.INVALID> - 2018-12-07 17:57 +0100
            Re: the famous formula Thomas Heger <ttt_heg@web.de> - 2018-12-08 14:03 +0100
              Re: the famous formula Gary Harnagel <hitlong@yahoo.com> - 2018-12-08 05:29 -0800
                Re: the famous formula Thomas Heger <ttt_heg@web.de> - 2018-12-08 18:43 +0100
                  [OT] Work (was: the famous formula) Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2018-12-08 21:53 +0100
                    Re: [OT] Work Thomas Heger <ttt_heg@web.de> - 2018-12-09 19:08 +0100
                      Re: [OT] Work Libor Striz <poutnik4REMOVEnntp@CAPITALSgmail.com.INVALID> - 2018-12-09 19:31 +0100
                      Re: [OT] Work Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2018-12-09 18:58 +0100
                        Re: [OT] Work Thomas Heger <ttt_heg@web.de> - 2018-12-10 18:52 +0100
                          Re: [OT] Work Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2018-12-10 22:28 +0100
                            Re: [OT] Work Thomas Heger <ttt_heg@web.de> - 2018-12-11 16:36 +0100
                              Re: [OT] Work Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2018-12-11 20:24 +0100
                  Re: the famous formula Gary Harnagel <hitlong@yahoo.com> - 2018-12-08 14:02 -0800
              Re: the famous formula Libor Striz <poutnik4REMOVEnntp@CAPITALSgmail.com.INVALID> - 2018-12-08 16:56 +0100
                Re: the famous formula Ejí Utorka <edew@aewedoc.cl> - 2018-12-08 16:05 +0000
                  Re: the famous formula Thomas Heger <ttt_heg@web.de> - 2018-12-08 18:35 +0100
                    Re: the famous formula Ejí Utorka <edew@aewedoc.cl> - 2018-12-08 17:58 +0000
                      Re: the famous formula Libor Striz <poutnik4REMOVEnntp@CAPITALSgmail.com.INVALID> - 2018-12-08 19:34 +0100
                        Re: the famous formula Ejí Utorka <edew@aewedoc.cl> - 2018-12-08 18:54 +0000
            Re: the famous formula Ejí Utorka <edew@aewedoc.cl> - 2018-12-08 16:09 +0000
    Re: the famous formula Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2018-12-06 22:16 +0100
    Re: the famous formula Odd Bodkin <bodkinodd@gmail.com> - 2018-12-07 16:07 +0000
    Re: the famous formula Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2018-12-07 22:47 +0100
    Re: the famous formula "Ross A. Finlayson" <ross.finlayson@gmail.com> - 2018-12-09 15:06 -0800
      Re: the famous formula benj <benj.fake@gmail.com> - 2018-12-12 13:44 -0500

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#479324

On Saturday, December 8, 2018 at 6:03:06 AM UTC-7, Thomas Heger wrote:
>
> Am 07.12.2018 um 17:57 schrieb Libor Striz:
> >
> > Work  is a scalar, not a vector.
> > 
> > dW = vec_F . d(vec_L)
> > W = path integral of dW along path L.
> > 
> > dW as a dot product of 2 vectors is a scalar.
> 
> I do not regard a distance as a vector.

(1) It is irrelevant what you "regard."
(2) It is obvious that "distance" IS a vector since I could specify the
distance between two cities as 100 miles, but you could get from one to
the other if you went in the wrong direction.  DUH!

> Sure. It is often done, but I do not agree.

Irrelevant.

“Opinion is really the lowest form of human knowledge.  It requires
no accountability, no understanding.” – Bill Bullard

“The world is changed by your example, not by your opinion.” – Paulo Coelho

"You are not entitled to your opinion. You are entitled to your informed
opinion.  No one is entitled to be ignorant." — Harlan Ellison

> The path along a line is not a distance, since a path is a function of time.
> 
> The reason why a distance is not a vector is this:
> a vector has a direction, but a distance between two spot on the same 
> line has no direction, since it is the same distance from A to B as from 
> B to A.

You are thinking one-dimensionally.

> Since force is directed, work should be a vector and the amount is then 
> energy.
> 
> TH

In case of one dimension, a force is just like a distance.  One-dimensional
thinking leads to confusion.

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#479349

Am 08.12.2018 um 14:29 schrieb Gary Harnagel:
> On Saturday, December 8, 2018 at 6:03:06 AM UTC-7, Thomas Heger wrote:
>>
>> Am 07.12.2018 um 17:57 schrieb Libor Striz:
>>>
>>> Work  is a scalar, not a vector.
>>>
>>> dW = vec_F . d(vec_L)
>>> W = path integral of dW along path L.
>>>
>>> dW as a dot product of 2 vectors is a scalar.
>>
>> I do not regard a distance as a vector.
> 
> (1) It is irrelevant what you "regard."
> (2) It is obvious that "distance" IS a vector since I could specify the
> distance between two cities as 100 miles, but you could get from one to
> the other if you went in the wrong direction.  DUH!


Distance is not about me or you. 'Distance' has a certain meaning and 
that requires similarity between distance from A to B in comparison to 
distance from B to A.

If you have a definition somehow different, then we have trouble in 
communication.

This is quite often a problem, since people use often the same words, 
but have not the same understanding about them.

Since you insist on a definition, which is violating my own 
understanding of the term, we should stop here and try to fix the 
communication problem.


TH

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#479385 — [OT] Work (was: the famous formula)

Thomas Heger wrote:
> Am 08.12.2018 um 14:29 schrieb Gary Harnagel:
>> On Saturday, December 8, 2018 at 6:03:06 AM UTC-7, Thomas Heger wrote:
>>> Am 07.12.2018 um 17:57 schrieb Libor Striz:
>>>>
>>>> Work  is a scalar, not a vector.
>>>>
>>>> dW = vec_F . d(vec_L)
>>>> W = path integral of dW along path L.
>>>>
>>>> dW as a dot product of 2 vectors is a scalar.
>>>
>>> I do not regard a distance as a vector.
>>
>> (1) It is irrelevant what you "regard."
>> (2) It is obvious that "distance" IS a vector since I could specify the
>> distance between two cities as 100 miles, but you could get from one to
>> the other if you went in the wrong direction.  DUH!
> 
> Distance is not about me or you. 'Distance' has a certain meaning

It has several:

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

> and that requires similarity between distance from A to B in comparison to 
                    ^^^^^^^^^^
> distance from B to A.

(The term that you were looking for is _equality_.)

No, it does not.

However, the statement that distance is a vector is *wrong*.  It can be
defined as the _norm_ (magnitude, length) of a vector instead (and since
the *Euclidean* norm of a vector is the same as that of its antiparallel
counterpart, the *Euclidean* distance between the cities is indeed the
same no matter in which city you start.)

Also, the formulation

>>>> dW = vec_F . d(vec_L)
>>>> W = path integral of dW along path L.

and consequently

  dW = F⃗ · dL⃗

is *wrong*; a path L can usually NOT be described by a constant vector.

The proper formulation is *either*

  W = ∫  F⃗⃗(r⃗) · dr⃗
       L

  (commonly: C instead of L; presumably for “curve”)

*or*

      r⃗₂
  W = ∫  F⃗⃗(r⃗) · dr⃗
      r⃗₁

with r⃗₁ and r⃗₂ specifying the end points of the path, and dr⃗ specifying
an infinitesimal _tangent vector on the path L_, respectively.  Since the
latter is seldom given, one can substitute dr⃗ = dr⃗∕dx dx to get

      r⃗₂
  W = ∫  [F⃗⃗(r⃗) · dr⃗∕dx] dx
      r⃗₁

with x being a given parameter of the path (parametrization).

A useful parametrization in physics is that using time t, because
instantaneous velocity (which can be calculated from the Newtonian
equation of motion) is defined as

  v⃗ = dr⃗∕dt,

so that

  W = ∫  F⃗⃗(r⃗) · dr⃗ = ∫  F⃗⃗(r⃗) · dr⃗(t)∕dt dt = ∫  F(r⃗) · v⃗(t) dt.
       C              C                       C

  [F⃗ = const. and constant direction then leads to the previously mentioned
   highschool-level definition of W = F s:

     W = ∫  F⃗ · v⃗(t) dt = F ∫  v(t) dt = F ∫  ds = F s.]
          C                  C              C

For another example (that we calculated in freshman physics), a spiral path
C can be defined by the vector

  r⃗ = (R cos φ, R sin φ, z = a φ); R, a = const.,

so that the work done by a force field F⃗(r⃗) on a particle moving along
this path can be calculated as

  W = ∫  F⃗⃗(r⃗) · dr⃗∕dφ dφ,
       C

with

      F⃗ = (F_x, F_y, F_z)
  dr⃗∕dφ = (−r sin φ, r cos φ, φ).

Using this to find a very nice, well-known result for a particle climbing
(on the spiral) from height z = 0 to height z = h if F⃗(r⃗) is the
gravitational force, is (and was) left as an exercise to the reader.

F’up2 sci.physics

-- 
PointedEars

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

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#479469 — Re: [OT] Work

Am 08.12.2018 um 21:53 schrieb Thomas 'PointedEars' Lahn:
> Thomas Heger wrote:
>> Am 08.12.2018 um 14:29 schrieb Gary Harnagel:
>>> On Saturday, December 8, 2018 at 6:03:06 AM UTC-7, Thomas Heger wrote:
>>>> Am 07.12.2018 um 17:57 schrieb Libor Striz:
>>>>>
>>>>> Work  is a scalar, not a vector.
>>>>>
>>>>> dW = vec_F . d(vec_L)
>>>>> W = path integral of dW along path L.
>>>>>
>>>>> dW as a dot product of 2 vectors is a scalar.
>>>>
>>>> I do not regard a distance as a vector.
>>>
>>> (1) It is irrelevant what you "regard."
>>> (2) It is obvious that "distance" IS a vector since I could specify the
>>> distance between two cities as 100 miles, but you could get from one to
>>> the other if you went in the wrong direction.  DUH!
>>
>> Distance is not about me or you. 'Distance' has a certain meaning
> 
> It has several:
> 
> <https://en.wikipedia.org/wiki/Distance>

Quote:

"Both distance and displacement measure the movement of an object. 
Distance cannot be negative, and never decreases. Distance is a scalar 
quantity, or a magnitude. "

So, essentially Wikipedia says the same as I said.


Distance is (according to wikipedia) a scalar quantity, not a vector.

Therefor work must be a vector quantity, since force is vectorial.

This should be obvious, if you imagine something like a box on a large 
plane, which is pushed forward.

This push is provided by, say, you and you apply a force, in the 
direction you want to push the box.

Since the job is kind of exhausting, you may call that 'work'.

The amount of work is measured in a scalar quantity called 'energy'.


TH

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#479470 — Re: [OT] Work

Thomas Heger <ttt_heg@web.de> Wrote in message:

> Distance is (according to wikipedia) a scalar quantity, not a vector.
> 
> Therefor work must be a vector quantity, since force is vectorial.
> 

Distance is a scalar, but a path differential is a vector.

When you walk, your walk does have a direction, does not it ?

The work differential
is a scalar product 
of the force vector
and the path differential,

and therefore it is a scalar.

You do agree the work done depends or force and path orientation,
 don't you ?

If the force is perpendicular to the path tangent, the work done
 is zero,
as scalar product of perpendicular vectors is zero scalar value.



-- 
Libor Striz aka Poutnik ( a pilgrim/wanderer/wayfarer)

"Humour is the only effective weapon against stupidity."
Miloš Forman


----Android NewsGroup Reader----
http://usenet.sinaapp.com/

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#479483 — Re: [OT] Work

Thomas Heger wrote:
> Am 08.12.2018 um 21:53 schrieb Thomas 'PointedEars' Lahn:
>> Thomas Heger wrote:
>>> Distance is not about me or you. 'Distance' has a certain meaning
>>
>> It has several:
>>
>> <https://en.wikipedia.org/wiki/Distance>
> 
> Quote:
> 
> "Both distance and displacement measure the movement of an object. 
> Distance cannot be negative, and never decreases. Distance is a scalar 
> quantity, or a magnitude. "

Once again you have not been reading comprehensively, in context.
The text that you are quoting refers to *Euclidean* space.

> So, essentially Wikipedia says the same as I said.

No, it does not.  You have to read in context.

To give you pause: The distance between two events in MINKOWSKI SPACE(TIME)
– which you claim to know and repeatedly stated to be the truth (over
special relativity, because you do not understand the connection between
them) –, which is given by

  ∆s² = c²∆t² − ∆x² − ∆y² − ∆z²,

can actually be negative.  We then call the events that are separated in
this way “spacelike-separated”, and the interval between them “spacelike”.

For example, in units where c = 1, the events

  e₁ = (0, 1, 2, 3)

and

  e₂ = (0, 2, 3, 4)

are spacelike-separated because

  ∆s² = ∆t² − ∆x² − ∆y² − ∆z²
      = (0 − 0)² − (2 − 1)² − (3 − 2)² − (4 − 3)²
      = 0 − 1 − 1 − 1
      = −3 < 0.

    [One can see this by calculating the spatial distance between them.
     It is

     √(∆x² + ∆y² + ∆z²) = √((2 − 1)² + (3 − 2)² + (4 − 3)²) = √3 ≈ 1.73

     But t(e₁) = t(e₂) here, so one would have to get instantaneously from
     one place to another, which means by infinite speed, which is certainly
     larger than the speed of light, c.]

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

The Minkowski metric is indefinite.  In general, distances can be negative
with any metric that is not positive-definite.

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

> [misconceptions]

-- 
PointedEars

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

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#479542 — Re: [OT] Work

Am 09.12.2018 um 18:58 schrieb Thomas 'PointedEars' Lahn:
> Thomas Heger wrote:
>> Am 08.12.2018 um 21:53 schrieb Thomas 'PointedEars' Lahn:
>>> Thomas Heger wrote:
>>>> Distance is not about me or you. 'Distance' has a certain meaning
>>>
>>> It has several:
>>>
>>> <https://en.wikipedia.org/wiki/Distance>
>>
>> Quote:
>>
>> "Both distance and displacement measure the movement of an object.
>> Distance cannot be negative, and never decreases. Distance is a scalar
>> quantity, or a magnitude. "
> 
> Once again you have not been reading comprehensively, in context.
> The text that you are quoting refers to *Euclidean* space.

I was actually perfectly happy with Euclidean space (in connection to 
the term 'distance').

> 
>> So, essentially Wikipedia says the same as I said.
> 
> No, it does not.  You have to read in context.
> 
> To give you pause: The distance between two events in MINKOWSKI SPACE(TIME)
> – which you claim to know and repeatedly stated to be the truth (over
> special relativity, because you do not understand the connection between
> them) –, which is given by
> 
>    ∆s² = c²∆t² − ∆x² − ∆y² − ∆z²,

Actually this is not called 'distance'. Instead the term 'interval' is used.

This has actually a reason, since it is not a good idea to use the same 
terms in entirely different contexts.

..

TH

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#479563 — Re: [OT] Work

Thomas Heger wrote:
> Am 09.12.2018 um 18:58 schrieb Thomas 'PointedEars' Lahn:
>> To give you pause: The distance between two events in MINKOWSKI SPACE(TIME)
>> – which you claim to know and repeatedly stated to be the truth (over
>> special relativity, because you do not understand the connection between
>> them) –, which is given by
>>
>>    ∆s² = c²∆t² − ∆x² − ∆y² − ∆z²,
> 
> Actually this is not called 'distance'. Instead the term 'interval' is used.

It is the *spacetime* distance.  Blithering fool!

-- 
PointedEars

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

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#479612 — Re: [OT] Work

Am 10.12.2018 um 22:28 schrieb Thomas 'PointedEars' Lahn:
> Thomas Heger wrote:
>> Am 09.12.2018 um 18:58 schrieb Thomas 'PointedEars' Lahn:
>>> To give you pause: The distance between two events in MINKOWSKI SPACE(TIME)
>>> – which you claim to know and repeatedly stated to be the truth (over
>>> special relativity, because you do not understand the connection between
>>> them) –, which is given by
>>>
>>>     ∆s² = c²∆t² − ∆x² − ∆y² − ∆z²,
>>
>> Actually this is not called 'distance'. Instead the term 'interval' is used.
> 
> It is the *spacetime* distance.  Blithering fool!
> 

No!

(Besides unnecessary insult..)

https://en.wikipedia.org/wiki/Spacetime#Spacetime_intervals

Quote:

"In four-dimensional spacetime, the analog to distance is the interval. "

'Analog' is not the same as 'the same'.


TH

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#479627 — Re: [OT] Work

Thomas Heger wrote:
> Am 10.12.2018 um 22:28 schrieb Thomas 'PointedEars' Lahn:
>> Thomas Heger wrote:
>>> Am 09.12.2018 um 18:58 schrieb Thomas 'PointedEars' Lahn:
>>>> To give you pause: The distance between two events in MINKOWSKI SPACE(TIME)
>>>> – which you claim to know and repeatedly stated to be the truth (over
>>>> special relativity, because you do not understand the connection between
>>>> them) –, which is given by
>>>>
>>>>     ∆s² = c²∆t² − ∆x² − ∆y² − ∆z²,
>>>
>>> Actually this is not called 'distance'. Instead the term 'interval' is used.
>>
>> It is the *spacetime* distance.  Blithering fool!
> 
> No!

Yes.

> (Besides unnecessary insult..)

This is a statement of fact.  The record shows.

> https://en.wikipedia.org/wiki/Spacetime#Spacetime_intervals
> 
> Quote:
> 
> "In four-dimensional spacetime, the analog to distance is the interval. "
> 
> 'Analog' is not the same as 'the same'.

I do not have as much free time as you probably unemployed or retired
wannabe who bases his "knowledge" on single sentences from Wikipedia,
and I have better things to do than to try to refute all the nonsense
that you claim.

Google “spacetime distance”.  Consider that it is the result of applying
the Minkowski *metric*.  Look up what that word means.

EOD

-- 
PointedEars

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

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#479394

On Saturday, December 8, 2018 at 10:43:45 AM UTC-7, Thomas Heger wrote:
>
> Am 08.12.2018 um 14:29 schrieb Gary Harnagel:
> >
> > On Saturday, December 8, 2018 at 6:03:06 AM UTC-7, Thomas Heger wrote:
> > >
> > > I do not regard a distance as a vector.
> > 
> > (1) It is irrelevant what you "regard."
> > (2) It is obvious that "distance" IS a vector since I could specify the
> > distance between two cities as 100 miles, but you could get from one to
> > the other if you went in the wrong direction.  DUH!
> 
> Distance is not about me or you.

It could be, as I used it.  You just made one of those "not even wrong"
assertions.

> 'Distance' has a certain meaning and that requires similarity between
> distance from A to B in comparison to distance from B to A.

Another insipid assertion.  Of COURSE there's a comparison.  It's just
geometry and mathematics.  One may use d as a distance without direction
(in which case it's a scalr) or one may use it WITH direction (in which
case it's a vector).  But to claim that it's NEVER a vector is just plain
wrong.

If A is stationary and B is at x = 4 and y = 3, then the distance from
A to B is d = 5 and the direction is Theta = arctan(0.75), which
proves that it's a vector in this case.

> If you have a definition somehow different, then we have trouble in 
> communication.

Or someone has a problem with rationality.

> This is quite often a problem, since people use often the same words, 
> but have not the same understanding about them.

I think everyone understands who is being irrational.

> Since you insist on a definition, which is violating my own 
> understanding of the term, we should stop here and try to fix the 
> communication problem.
> 
> TH

“People love answers, but only as long as they are the ones who came up with
them.” ― Criss Jami

You can tell who has problems here because YOU have come up with your own
definition and many have been telling you the correct definitions (which
aren't their own definitions).

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#479337

Thomas Heger <ttt_heg@web.de> Wrote in message:
> Am 07.12.2018 um 17:57 schrieb Libor Striz:
>
>> 
>> Work  is a scalar, not a vector.
>> 
>> dW = vec_F . d(vec_L)
>> W = path integral of dW along path L.
>> 
>> dW as a dot product of 2 vectors is a scalar.
>> 
> 
> I do not regard a distance as a vector.

Neither do I. But the infinitesimal path is, especially on context 
of the definition of the work  diferential
as scalar product of 2 vectors
> 
dW = F . dL = |F| * |dL| * cos(fi)
Where fi is the angle between vector of force and infinitesimal
 vector of path.

-- 
Libor Striz aka Poutnik ( a pilgrim/wanderer/wayfarer)

"Humour is the only effective weapon against stupidity."
Miloš Forman


----Android NewsGroup Reader----
http://usenet.sinaapp.com/

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#479339

Libor Striz wrote:

> Thomas Heger <ttt_heg@web.de> Wrote in message:
>> Am 07.12.2018 um 17:57 schrieb Libor Striz:
>>> Work  is a scalar, not a vector.
>>> dW = vec_F . d(vec_L)
>>> W = path integral of dW along path L.
>>> dW as a dot product of 2 vectors is a scalar.
>>> 
>> I do not regard a distance as a vector.
> 
> Neither do I. But the infinitesimal path is, especially on context of
> the definition of the work  diferential as scalar product of 2 vectors 
> dW = F . dL = |F| * |dL| * cos(fi)
> Where fi is the angle between vector of force and infinitesimal
>  vector of path.

dL is the vector, not the L, One more proof on your incompetency and the 
lack of education. You just brought your country in eternal shame. Without 
the bulgarians you would be speaking german.

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#479348

Am 08.12.2018 um 17:05 schrieb Ejí Utorka:
> Libor Striz wrote:
> 
>> Thomas Heger <ttt_heg@web.de> Wrote in message:
>>> Am 07.12.2018 um 17:57 schrieb Libor Striz:
>>>> Work  is a scalar, not a vector.
>>>> dW = vec_F . d(vec_L)
>>>> W = path integral of dW along path L.
>>>> dW as a dot product of 2 vectors is a scalar.
>>>>
>>> I do not regard a distance as a vector.
>>
>> Neither do I. But the infinitesimal path is, especially on context of
>> the definition of the work  diferential as scalar product of 2 vectors
>> dW = F . dL = |F| * |dL| * cos(fi)
>> Where fi is the angle between vector of force and infinitesimal
>>   vector of path.
> 
> dL is the vector, not the L, 


Well, no.

Actually force is a vectorial quantity, while a line between point A and 
B is not.

'Distance' is not meant a the integral of tiny movements, which a 
certain objects performs, if it is pushed around.

Distance is meant as the length of that path, not as the path itself.

(This is a small difference, but important in this context.)

A length is usually a scalar, not a vector.

The movement of an object along a certain path is a function of time.

Since distance is not a function of time (of course), the path and the 
distance are different things.

Another thing to confuse with distance is also called 'path'.

This is similar to a road or other type of constraints, by which 
movement is guided along a certain - well - path.



TH

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#479351

Thomas Heger wrote:

> Am 08.12.2018 um 17:05 schrieb Ejí Utorka:
>> Libor Striz wrote:
>> 
>>> Thomas Heger <ttt_heg@web.de> Wrote in message:
>>>> Am 07.12.2018 um 17:57 schrieb Libor Striz:
>>>>> Work  is a scalar, not a vector.
>>>>> dW = vec_F . d(vec_L)
>>>>> W = path integral of dW along path L.
>>>>> dW as a dot product of 2 vectors is a scalar.
>>>>>
>>>> I do not regard a distance as a vector.
>>>
>>> Neither do I. But the infinitesimal path is, especially on context of
>>> the definition of the work  diferential as scalar product of 2 vectors
>>> dW = F . dL = |F| * |dL| * cos(fi)
>>> Where fi is the angle between vector of force and infinitesimal
>>>   vector of path.
>> 
>> dL is the vector, not the L,
> 
> Well, no.
> A length is usually a scalar, not a vector.

But that's not a length. Reread what I wrote. Basic physics. When you 
differentiate something. What's wrong with you people.

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#479361

Ejí Utorka <edew@aewedoc.cl> Wrote in message:
> Thomas Heger wrote:
> 
>> Am 08.12.2018 um 17:05 schrieb Ejí Utorka:
>>> Libor Striz wrote:
>>> 
>>>> Thomas Heger <ttt_heg@web.de> Wrote in message:
>>>>> Am 07.12.2018 um 17:57 schrieb Libor Striz:
>>>>>> Work  is a scalar, not a vector.
>>>>>> dW = vec_F . d(vec_L)
>>>>>> W = path integral of dW along path L.
>>>>>> dW as a dot product of 2 vectors is a scalar.
>>>>>>
>>>>> I do not regard a distance as a vector.
>>>>
>>>> Neither do I. But the infinitesimal path is, especially on context of
>>>> the definition of the work  diferential as scalar product of 2 vectors
>>>> dW = F . dL = |F| * |dL| * cos(fi)
>>>> Where fi is the angle between vector of force and infinitesimal
>>>>   vector of path.
>>> 
>>> dL is the vector, not the L,
>> 
>> Well, no.
>> A length is usually a scalar, not a vector.
> 
> But that's not a length. Reread what I wrote. Basic physics. When you 
> differentiate something. What's wrong with you people.
> 

Do not confuse a distance and a length of a path.

The closed path length around a circle is 2.pi.r.
The distance between its endpoints is zero.
The elements dL along this circular path are vectors  and F . dL
 gives infinitesimal scalar of work dW.

-- 
Libor Striz aka Poutnik ( a pilgrim/wanderer/wayfarer)

"Humour is the only effective weapon against stupidity."
Miloš Forman


----Android NewsGroup Reader----
http://usenet.sinaapp.com/

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#479372

Libor Striz wrote:

>>>>> Neither do I. But the infinitesimal path is, especially on context
>>>>> of the definition of the work  diferential as scalar product of 2
>>>>> vectors dW = F . dL = |F| * |dL| * cos(fi)
>>>>> Where fi is the angle between vector of force and infinitesimal
>>>>>   vector of path.
>>>> 
>>>> dL is the vector, not the L,
>>> 
>>> Well, no.
>>> A length is usually a scalar, not a vector.
>> 
>> But that's not a length. Reread what I wrote. Basic physics. When you
>> differentiate something. What's wrong with you people.
>
> Do not confuse a distance and a length of a path.

What you claimed it was a scalar in that expression is a vector. The 
basics you learn, in kindergarten, for gosh sake. In which country you are 
a resident of?

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#479340

Libor Striz wrote:

> Thomas Heger <ttt_heg@web.de> Wrote in message:
>> 
>> Energy is a scalar unit, hence cannot become negative and has no
>> direction.
> 
> Being a scalar does not say it cannot be negative.

There are no negative things in this universe. The dipoles, where 
applicable, are about polarity, not negativiness. What you erroneously 
you'll been fooled along your education system of your country, is just a 
point on a arbitrary scale. Basic physics. What a shame.

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#479209

RichD wrote:
> Everybody knows E = mc², and figures it's well understood. 
> I disagree.  It all depends on what '=' means.

It means what it means in mathematics: The left-hand side is *equal* to the
right-hand side.  (This works because energy can have units of [mass] ×
[speed]².  Consider, e.g., Newtonian kinetic energy T = ½ m v².)

Only that you either wrote the left-hand side wrong or used a deprecated
concept for mass m (“relativistic mass”).

You should have written

  E₀ = m c²

or

  E  = m_rel c²

instead.

> By analogy, […]

You cannot understand this by (armchair) philosophy.  Give it up while you
still can, and learn the underlying mathematics instead.  It is really not
very hard.

Most symbols used in physics have physical meaning.

You cannot understand physics without understanding the underlying concepts
(here: energy, mass, and speed) and mathematics (here: 1+3-dimensional
pseudo-Euclidean differential geometry) *first*.

-- 
PointedEars

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

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#479240

RichD <r_delaney2001@yahoo.com> wrote:
> Everybody knows E = mc², and figures it's well understood. 
> I disagree.  It all depends on what '=' means.
> 
> By analogy, consider the following cases:
> Al and Bob are identical twins; i.e. Al = Bob
> 
> i)  They attend a party, each wearing a name tag.
> Everybody can see they're identical, that the name tags are immaterial.
> 
> ii)  They attend a party, each wearing a different mask.  
> No one knows which is which, but all agree, they're 
> still identical, the masks are immaterial.
> 
> iii)  One of them dies, but no one knows which.  Meanwhile, 
> the survivor takes the deceased's identity; that is, Al is 
> now Bob, or vice versa.   Are they still identical?
> 
> iv)  On a daily basis, they display contrasting 
> personalities;  on Monday, Al is outgoing, Bob withdrawn; 
> on Tuesday, they switch.  Are they still identical?
> 
> Now, which of the above - or some other analogy - applies 
> to the famous formula?  What is the meaning of 'equal'?
> 
> --
> Rich
> 

This does not mean that energy is the same thing as mass. 

What it means is that there is a certain amount of energy, which
contributes to total energy like other contributions, that is associated
with mass. And this is the relation that ties the quantity of energy to the
quantity of mass. That’s all. 

-- 
Odd Bodkin — Maker of fine toys, tools, tables

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