Groups > sci.physics.relativity > #599489 > unrolled thread

Re: Kinetic Energy formula check - a series of short burn rockets, and see how the velocity adds up.

Started by	Thomas Heger <ttt_heg@web.de>
First post	2023-01-12 08:31 +0100
Last post	2023-01-19 00:39 -0800
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#599489 — Re: Kinetic Energy formula check - a series of short burn rockets, and see how the velocity adds up.

From	Thomas Heger <ttt_heg@web.de>
Date	2023-01-12 08:31 +0100
Subject	Re: Kinetic Energy formula check - a series of short burn rockets, and see how the velocity adds up.
Message-ID	<k29ra7F4a40U1@mid.individual.net>

Am 09.01.2023 um 15:13 schrieb Joe:
> On Mon, 09 Jan 2023 09:07:50 +0100
> Thomas Heger <ttt_heg@web.de> wrote:
>
>> Am 08.01.2023 um 10:36 schrieb Dave:
>>> Is it v or v^2?
>>>
>>> Is this formula E=0.5mv^2 correct, or is it more like E= mv?
>>
>>
>> That should depend on the used units for E, m and v.
>>
>> As unit systems have different degrees of internal consistency, you
>> should certainly be able to find an example for both factors.
>>
>>
>> I usually use SI units only and would get 0.5 as factor, but have not
>> verified the exponent 2 myself.
>>
>> In general I would prefer the quantity momentum over energy, because
>> v is frame dependent, hence also kinetic energy.
>>
>> Then I would like to compare conservation of momentum and
>> conservation of energy, but suggest choosing conservation of momentum
>> over conservation of energy.
>>
>> TH
>
> The whole question revolves around kinetic energy being a different
> thing from momentum, not just being a different word for it. To begin
> with, we have no idea of the absolute kinetic energy or the absolute
> momentum of an object, because we have no idea how fast an object is
> moving, and according Einstein, we never can know it. So we work on
> relative quantities, generally relative to 'stationary with respect to
> the bit of Earth's surface where the action takes place'.

Momentum and kinetic energy adress different things, but are closely 
related.

I chose as example a cannon ball flying through an empty 
gravitation-free SRT like space.

Now we don't know the velocity of the cannon ball, because we have no 
'anchor' to measure velocity against.

But that cannon ball shall hit a spaceship, which drifts around that 
void, too.

Now we have an anchor point, which is that spaceship and the point of 
its hull that the cannonball hits.

Now we see, that we need to take the relative velocity between ball and 
spaceship as velocity v and cannot use any other velocity.

In the case of collision between ball and ship the momentum of the ball 
is transferred to the ships armourment, as is also the kinetic energy of 
the ball.

But obviously relative velocity is the thing which matters, while 
absolute velocity wouldn't.

If we would use the SRT setting and would allow arbitrary velocities and 
arbitrary frames of references, then we would not have proportional 
relations between momentum and kinetic energy, because one behaves 
quatratic and one linear, if v is altered.

So, a different velocity caused by external changes of the position of 
observation would alter the relation between inertia and energy inside 
that cannon ball, what cannot possibly be the case. Therefore velocity v 
has to be the velocity in respect to the target, which is not arbitrary 
and not subject to decisions of an external observer.

> The kinetic energy of an object of mass m moving at velocity v is the
> amount of energy required to raise the mass from a stationary position
> to the velocity v, or to slow it down to stationary. You can start from
> first principles with length and time, going through force,
> acceleration and work, or you can work directly with velocity as the
> independent variable.

SRT does not know any 'stationary positions', because positions are 
always relative to something.

That somethings is also relative to something and so forth.

In the end we have a final point and still don't know, whether or not 
that point moves.

...

TH

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#599512

From	Evangelista Barzetti <magm@hyojmkib.vi>
Date	2023-01-12 16:45 +0000
Message-ID	<tppdfj$1aks5$1@dont-email.me>
In reply to	#599489

Thomas Heger wrote:

> Momentum and kinetic energy adress different things, but are closely
> related. I chose as example a cannon ball flying through an empty
> gravitation-free SRT like space.

not sure, but here's how Relativity is to be pictured as "science". When 
you talk to Einstine, you talk to science.

＂Coincidences are the leading cause of deaths＂ Coincidence theory. 
https://%62%69%74%63%68%75%74%65.com/%76%69%64%65%6f/4onY7JdMkUC8

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#599513

From	Otto Fiscella <tfit@tiselelc.it>
Date	2023-01-12 16:51 +0000
Message-ID	<tppdqs$1aks5$2@dont-email.me>
In reply to	#599489

Thomas Heger wrote:

> Momentum and kinetic energy adress different things, but are closely
> related. I chose as example a cannon ball flying through an empty
> gravitation-free SRT like space.

wow, forgot the other _deep_scientist_ in Relativity. Corruption all 
levels, in capitalism, my friend.

Neil deGrasse Tyson Doesn't Want You Asking Questions About The Vaccine 
https://%62%69%74%63%68%75%74%65.com/%76%69%64%65%6f/CzT9zJfvafVK

＂Coincidences are the leading cause of deaths＂ Coincidence theory.
https://%62%69%74%63%68%75%74%65.com/%76%69%64%65%6f/4onY7JdMkUC8

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#599543 — Re: Kinetic Energy formula check - a series of short burn rockets, and see how the velocity adds up.

From	Thomas Heger <ttt_heg@web.de>
Date	2023-01-13 08:23 +0100
Subject	Re: Kinetic Energy formula check - a series of short burn rockets, and see how the velocity adds up.
Message-ID	<k2cf81Fglm9U1@mid.individual.net>
In reply to	#599513

Am 12.01.2023 um 17:51 schrieb Otto Fiscella:
> Thomas Heger wrote:
>
>> Momentum and kinetic energy adress different things, but are closely
>> related. I chose as example a cannon ball flying through an empty
>> gravitation-free SRT like space.
>
> wow, forgot the other _deep_scientist_ in Relativity. Corruption all
> levels, in capitalism, my friend.
>

In SRT Einstein used the velocity v, but meant velocity of an object 
relative to space.

But that definition would violate the very idea of SRT itself.

I meant, that SRT-like movements would require to different 'anchors' to 
measure velocity against like the relation to a target, which a 
cannon-ball hits.

The setting of SRT would actually allow to use other frames of 
references as 'achors'. But in this case velocity v would become a 
variable. But that could (for different v) alter the relation between 
inertia and kinetic energy of a connon-ball in flight, just by choosing 
a different coordinate system, what cannot possibly be the case.

TH

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#599579 — Re: Kinetic Energy formula check - a series of short burn rockets, and see how the velocity adds up.

From	Tom Roberts <tjoberts137@sbcglobal.net>
Date	2023-01-13 20:24 -0600
Subject	Re: Kinetic Energy formula check - a series of short burn rockets, and see how the velocity adds up.
Message-ID	<pcCcnVIlQen-j1_-nZ2dnZfqlJ9h4p2d@giganews.com>
In reply to	#599543

On 1/13/23 1:23 AM, Thomas Heger wrote:
> In SRT Einstein used the velocity v, but meant velocity of an object 
> relative to space.

You just keep making stuff up and pretending it is true. This is
BLATANTLY WRONG. If you had actually read Einstein's 1905 paper on SR,
you would know that every velocity he mentioned was relative to a
specified set of inertial coordinates.

> [.... more nonsensical, made-up stuff]

His paper is quite clear: no "anchors" or "targets" are ever used to
measure velocities; each and every time he used a set of inertial
coordinates.

Tom Roberts

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#599580 — Re: Kinetic Energy formula check - a series of short burn rockets, and see how the velocity adds up.

From	Maciej Wozniak <maluwozniak@gmail.com>
Date	2023-01-13 22:21 -0800
Subject	Re: Kinetic Energy formula check - a series of short burn rockets, and see how the velocity adds up.
Message-ID	<f8345862-e449-400a-aafa-87ad4b1e72d1n@googlegroups.com>
In reply to	#599579

On Saturday, 14 January 2023 at 03:24:42 UTC+1, Tom Roberts wrote:
> On 1/13/23 1:23 AM, Thomas Heger wrote: 
> > In SRT Einstein used the velocity v, but meant velocity of an object 
> > relative to space.
> You just keep making stuff up and pretending it is true. This is 
> BLATANTLY WRONG. If you had actually read Einstein's 1905 paper on SR, 
> you would know that 

That we're FORCED!!! To THE BEST WAY!!!!

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#599583 — Re: Kinetic Energy formula check - a series of short burn rockets, and see how the velocity adds up.

From	Thomas Heger <ttt_heg@web.de>
Date	2023-01-14 10:00 +0100
Subject	Re: Kinetic Energy formula check - a series of short burn rockets, and see how the velocity adds up.
Message-ID	<k2f99sFttscU1@mid.individual.net>
In reply to	#599579

Am 14.01.2023 um 03:24 schrieb Tom Roberts:
> On 1/13/23 1:23 AM, Thomas Heger wrote:
>> In SRT Einstein used the velocity v, but meant velocity of an object
>> relative to space.
>
> You just keep making stuff up and pretending it is true. This is
> BLATANTLY WRONG. If you had actually read Einstein's 1905 paper on SR,
> you would know that every velocity he mentioned was relative to a
> specified set of inertial coordinates.

This 'specified set of coordinates' needs to be specidied, too. 
Therefore, we need another set of specified coordinates to specify the 
previous ones.

And so on and on, with infinite regress.

>
>> [.... more nonsensical, made-up stuff]
>
> His paper is quite clear: no "anchors" or "targets" are ever used to
> measure velocities; each and every time he used a set of inertial
> coordinates.
>

He could have used 'mumble' also (instead of 'inertial coordinates').

Contrary to your view, you need a starting point for a position vector. 
And that starting point needs also a vector, which defines, where that 
point is located. (and so forth...)

TH

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#599586 — Re: Kinetic Energy formula check - a series of short burn rockets, and see how the velocity adds up.

From	JanPB <filmart@gmail.com>
Date	2023-01-14 02:58 -0800
Subject	Re: Kinetic Energy formula check - a series of short burn rockets, and see how the velocity adds up.
Message-ID	<ae680a29-ddf7-44c4-a6cd-e589bb192781n@googlegroups.com>
In reply to	#599583

On Saturday, January 14, 2023 at 1:00:48 AM UTC-8, Thomas Heger wrote:
> Am 14.01.2023 um 03:24 schrieb Tom Roberts: 
> > On 1/13/23 1:23 AM, Thomas Heger wrote: 
> >> In SRT Einstein used the velocity v, but meant velocity of an object 
> >> relative to space. 
> > 
> > You just keep making stuff up and pretending it is true. This is 
> > BLATANTLY WRONG. If you had actually read Einstein's 1905 paper on SR, 
> > you would know that every velocity he mentioned was relative to a 
> > specified set of inertial coordinates.
> This 'specified set of coordinates' needs to be specidied, too. 
> Therefore, we need another set of specified coordinates to specify the 
> previous ones. 
> 
> And so on and on, with infinite regress.

No. It doesn't work that way.

--
Jan

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#599622 — Re: Kinetic Energy formula check - a series of short burn rockets, and see how the velocity adds up.

From	Thomas Heger <ttt_heg@web.de>
Date	2023-01-15 08:12 +0100
Subject	Re: Kinetic Energy formula check - a series of short burn rockets, and see how the velocity adds up.
Message-ID	<k2hnbiFaphqU2@mid.individual.net>
In reply to	#599586

Am 14.01.2023 um 11:58 schrieb JanPB:
> On Saturday, January 14, 2023 at 1:00:48 AM UTC-8, Thomas Heger wrote:
>> Am 14.01.2023 um 03:24 schrieb Tom Roberts:
>>> On 1/13/23 1:23 AM, Thomas Heger wrote:
>>>> In SRT Einstein used the velocity v, but meant velocity of an object
>>>> relative to space.
>>>
>>> You just keep making stuff up and pretending it is true. This is
>>> BLATANTLY WRONG. If you had actually read Einstein's 1905 paper on SR,
>>> you would know that every velocity he mentioned was relative to a
>>> specified set of inertial coordinates.
>> This 'specified set of coordinates' needs to be specidied, too.
>> Therefore, we need another set of specified coordinates to specify the
>> previous ones.
>>
>> And so on and on, with infinite regress.
>
> No. It doesn't work that way.

sure, infinite regress does not work.

But what else do you suggest?

TH

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#599649 — Re: Kinetic Energy formula check - a series of short burn rockets, and see how the velocity adds up.

From	JanPB <filmart@gmail.com>
Date	2023-01-15 12:13 -0800
Subject	Re: Kinetic Energy formula check - a series of short burn rockets, and see how the velocity adds up.
Message-ID	<1c40752b-50d6-4c70-98ea-3ad0bfde5ad0n@googlegroups.com>
In reply to	#599622

On Saturday, January 14, 2023 at 11:12:54 PM UTC-8, Thomas Heger wrote:
> Am 14.01.2023 um 11:58 schrieb JanPB: 
> > On Saturday, January 14, 2023 at 1:00:48 AM UTC-8, Thomas Heger wrote: 
> >> Am 14.01.2023 um 03:24 schrieb Tom Roberts: 
> >>> On 1/13/23 1:23 AM, Thomas Heger wrote: 
> >>>> In SRT Einstein used the velocity v, but meant velocity of an object 
> >>>> relative to space. 
> >>> 
> >>> You just keep making stuff up and pretending it is true. This is 
> >>> BLATANTLY WRONG. If you had actually read Einstein's 1905 paper on SR, 
> >>> you would know that every velocity he mentioned was relative to a 
> >>> specified set of inertial coordinates. 
> >> This 'specified set of coordinates' needs to be specidied, too. 
> >> Therefore, we need another set of specified coordinates to specify the 
> >> previous ones. 
> >> 
> >> And so on and on, with infinite regress. 
> > 
> > No. It doesn't work that way.
> sure, infinite regress does not work. 
> 
> But what else do you suggest? 

It was described in Einstein's 1905 paper. It's a process with no infinite regress.

--
Jan

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#599668 — Re: Kinetic Energy formula check - a series of short burn rockets, and see how the velocity adds up.

From	Thomas Heger <ttt_heg@web.de>
Date	2023-01-16 08:08 +0100
Subject	Re: Kinetic Energy formula check - a series of short burn rockets, and see how the velocity adds up.
Message-ID	<k2kbehFn2nnU1@mid.individual.net>
In reply to	#599649

Am 15.01.2023 um 21:13 schrieb JanPB:
> On Saturday, January 14, 2023 at 11:12:54 PM UTC-8, Thomas Heger wrote:
>> Am 14.01.2023 um 11:58 schrieb JanPB:
>>> On Saturday, January 14, 2023 at 1:00:48 AM UTC-8, Thomas Heger wrote:
>>>> Am 14.01.2023 um 03:24 schrieb Tom Roberts:
>>>>> On 1/13/23 1:23 AM, Thomas Heger wrote:
>>>>>> In SRT Einstein used the velocity v, but meant velocity of an object
>>>>>> relative to space.
>>>>>
>>>>> You just keep making stuff up and pretending it is true. This is
>>>>> BLATANTLY WRONG. If you had actually read Einstein's 1905 paper on SR,
>>>>> you would know that every velocity he mentioned was relative to a
>>>>> specified set of inertial coordinates.
>>>> This 'specified set of coordinates' needs to be specidied, too.
>>>> Therefore, we need another set of specified coordinates to specify the
>>>> previous ones.
>>>>
>>>> And so on and on, with infinite regress.
>>>
>>> No. It doesn't work that way.
>> sure, infinite regress does not work.
>>
>> But what else do you suggest?
>
> It was described in Einstein's 1905 paper. It's a process with no infinite regress.

Einstein 'defined' an inertial frame as coordinate system, in which the 
equations of Newton's mechanics hold good.

I wrote, that Newton was an earthling and the surface of our home planet 
is not, what we would call 'inertial frame of reference' today.

Such inertial frames require absense of gravity, which we earthlings 
obviously cannot provide.

But in such a dark and gravity free inertial frame, you have abolutely 
nothing, which could eventually help you to measure absolute velocity.

In that scenario you always need something, where you could base your 
position vectors on.

You could place a 'buoy' somewhere as reference, but don't know its 
velocity neither.

So, you need another buoy, to reference the position of the first buoy. 
And that buoy needs an anchor, too, what lets you end up with infinite 
regress.

TH

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#599673 — Re: Kinetic Energy formula check - a series of short burn rockets, and see how the velocity adds up.

From	JanPB <filmart@gmail.com>
Date	2023-01-16 02:09 -0800
Subject	Re: Kinetic Energy formula check - a series of short burn rockets, and see how the velocity adds up.
Message-ID	<223aba72-4402-4849-9c77-c2e7bc650c34n@googlegroups.com>
In reply to	#599668

On Sunday, January 15, 2023 at 11:08:06 PM UTC-8, Thomas Heger wrote:
> Am 15.01.2023 um 21:13 schrieb JanPB: 
> > On Saturday, January 14, 2023 at 11:12:54 PM UTC-8, Thomas Heger wrote: 
> >> Am 14.01.2023 um 11:58 schrieb JanPB: 
> >>> On Saturday, January 14, 2023 at 1:00:48 AM UTC-8, Thomas Heger wrote: 
> >>>> Am 14.01.2023 um 03:24 schrieb Tom Roberts: 
> >>>>> On 1/13/23 1:23 AM, Thomas Heger wrote: 
> >>>>>> In SRT Einstein used the velocity v, but meant velocity of an object 
> >>>>>> relative to space. 
> >>>>> 
> >>>>> You just keep making stuff up and pretending it is true. This is 
> >>>>> BLATANTLY WRONG. If you had actually read Einstein's 1905 paper on SR, 
> >>>>> you would know that every velocity he mentioned was relative to a 
> >>>>> specified set of inertial coordinates. 
> >>>> This 'specified set of coordinates' needs to be specidied, too. 
> >>>> Therefore, we need another set of specified coordinates to specify the 
> >>>> previous ones. 
> >>>> 
> >>>> And so on and on, with infinite regress. 
> >>> 
> >>> No. It doesn't work that way. 
> >> sure, infinite regress does not work. 
> >> 
> >> But what else do you suggest? 
> > 
> > It was described in Einstein's 1905 paper. It's a process with no infinite regress.
> Einstein 'defined' an inertial frame as coordinate system, in which the 
> equations of Newton's mechanics hold good. 
> 
> I wrote, that Newton was an earthling and the surface of our home planet 
> is not, what we would call 'inertial frame of reference' today. 
> 
> Such inertial frames require absense of gravity, which we earthlings 
> obviously cannot provide. 
> 
> But in such a dark and gravity free inertial frame, you have abolutely 
> nothing, which could eventually help you to measure absolute velocity. 
> 
> In that scenario you always need something, where you could base your 
> position vectors on. 
> 
> You could place a 'buoy' somewhere as reference, but don't know its 
> velocity neither. 
> 
> So, you need another buoy, to reference the position of the first buoy. 
> And that buoy needs an anchor, too, what lets you end up with infinite 
> regress. 

Nonsense.

--
Jan

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#599722 — Re: Kinetic Energy formula check - a series of short burn rockets, and see how the velocity adds up.

From	Thomas Heger <ttt_heg@web.de>
Date	2023-01-17 08:39 +0100
Subject	Re: Kinetic Energy formula check - a series of short burn rockets, and see how the velocity adds up.
Message-ID	<k2n1m6F57fpU2@mid.individual.net>
In reply to	#599673

Am 16.01.2023 um 11:09 schrieb JanPB:

>
> Nonsense.
>


This argument is a little weak.

You should at least write, wtih which particular statement you disagree.


TH
>

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#599724 — Re: Kinetic Energy formula check - a series of short burn rockets, and see how the velocity adds up.

From	Maciej Wozniak <maluwozniak@gmail.com>
Date	2023-01-17 00:28 -0800
Subject	Re: Kinetic Energy formula check - a series of short burn rockets, and see how the velocity adds up.
Message-ID	<8f569295-de40-41d4-8014-d26008c11854n@googlegroups.com>
In reply to	#599722

On Tuesday, 17 January 2023 at 08:39:53 UTC+1, Thomas Heger wrote:
> Am 16.01.2023 um 11:09 schrieb JanPB: 
> 
> > 
> > Nonsense. 
> > 
> 
> 
> This argument is a little weak. 
> 
> You should at least write, wtih which particular statement you disagree. 

No, he shouldn't. He should wave his arms and
scream; that's what one is  expecting from a 
fanatic idiot and that's what a fanatic idiot
is performing.

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#599745 — Re: Kinetic Energy formula check - a series of short burn rockets, and see how the velocity adds up.

From	Volney <volney@invalid.invalid>
Date	2023-01-17 13:04 -0500
Subject	Re: Kinetic Energy formula check - a series of short burn rockets, and see how the velocity adds up.
Message-ID	<tq6nuu$3b8ve$1@dont-email.me>
In reply to	#599668

On 1/16/2023 2:08 AM, Thomas Heger wrote:
> Am 15.01.2023 um 21:13 schrieb JanPB:
>> On Saturday, January 14, 2023 at 11:12:54 PM UTC-8, Thomas Heger wrote:
>>> Am 14.01.2023 um 11:58 schrieb JanPB:
>>>> On Saturday, January 14, 2023 at 1:00:48 AM UTC-8, Thomas Heger wrote:
>>>>> Am 14.01.2023 um 03:24 schrieb Tom Roberts:
>>>>>> On 1/13/23 1:23 AM, Thomas Heger wrote:
>>>>>>> In SRT Einstein used the velocity v, but meant velocity of an object
>>>>>>> relative to space.
>>>>>>
>>>>>> You just keep making stuff up and pretending it is true. This is
>>>>>> BLATANTLY WRONG. If you had actually read Einstein's 1905 paper on 
>>>>>> SR,
>>>>>> you would know that every velocity he mentioned was relative to a
>>>>>> specified set of inertial coordinates.
>>>>> This 'specified set of coordinates' needs to be specidied, too.
>>>>> Therefore, we need another set of specified coordinates to specify the
>>>>> previous ones.
>>>>>
>>>>> And so on and on, with infinite regress.
>>>>
>>>> No. It doesn't work that way.
>>> sure, infinite regress does not work.
>>>
>>> But what else do you suggest?
>>
>> It was described in Einstein's 1905 paper. It's a process with no 
>> infinite regress.
> 
> Einstein 'defined' an inertial frame as coordinate system, in which the 
> equations of Newton's mechanics hold good.
> 
> I wrote, that Newton was an earthling and the surface of our home planet 
> is not, what we would call 'inertial frame of reference' today.

Einstein didn't state that this frame, where the equations of Newton's 
mechanics hold good, was being tested on earth. Remember, frames are 
infinite in extent and comprise the entire universe.
> 
> Such inertial frames require absense of gravity, which we earthlings 
> obviously cannot provide.

As usual in physics, especially then, things are tested to within an 
error limit, where it can be shown the error from the existence of 
gravity or whatever is smaller than measurement errors or outcome error.

Secondly, this is theoretical, it's what happens when there is no 
gravity even if such a situation is difficult or impossible to reproduce 
in real life. Just like Einstein's trains, moving at a substantial 
fraction of c, with observers able to time flashes from lightning bolts 
as a train passes an embankment aren't real.

> But in such a dark and gravity free inertial frame, you have abolutely 
> nothing, which could eventually help you to measure absolute velocity.

And Einstein doesn't try to use any absolute velocity. He says simply 
here's a frame where the equations of Newton's mechanics hold good. Are 
you going to complain that Einstein didn't discuss moving objects around 
and accelerating them to test Newton's mechanics?
> 
> In that scenario you always need something, where you could base your 
> position vectors on.

You, the observer, say "Here's the origin".
> 
> You could place a 'buoy' somewhere as reference, but don't know its 
> velocity neither.

Doesn't matter. Observer considers himself stationary and verifies 
Newton's mechanics.

Remember, Einstein was writing for other physicists who understood 
perfectly what the equations of Newton's mechanics hold good means, 
there was no need for him to write another 5000 pages to explain all of 
that.

You come up with some of the craziest nitpicks, no wonder you found 400+ 
"errors" where there are none.

> So, you need another buoy, to reference the position of the first buoy.

What first buoy? Where the observer declares the origin and declares it 
to be stationary? Remember, these are user defined, frames are infinite 
in extent, and can be anywhere the observer wants.

> And that buoy needs an anchor, too, what lets you end up with infinite 
> regress.

No regression needed. If you are unable to try to understand a paper 
written for physicists just leave a marker and declare it as at the 
origin and with zero velocity. Wait, you'll probably whine your little 
pebble marker has mass and therefore gravity, so...

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#599795 — Re: Kinetic Energy formula check - a series of short burn rockets, and see how the velocity adds up.

From	Thomas Heger <ttt_heg@web.de>
Date	2023-01-18 09:22 +0100
Subject	Re: Kinetic Energy formula check - a series of short burn rockets, and see how the velocity adds up.
Message-ID	<k2poiiFi1jiU1@mid.individual.net>
In reply to	#599745

Am 17.01.2023 um 19:04 schrieb Volney:

>> Such inertial frames require absense of gravity, which we earthlings
>> obviously cannot provide.
>
> As usual in physics, especially then, things are tested to within an
> error limit, where it can be shown the error from the existence of
> gravity or whatever is smaller than measurement errors or outcome error.
>
> Secondly, this is theoretical, it's what happens when there is no
> gravity even if such a situation is difficult or impossible to reproduce
> in real life. Just like Einstein's trains, moving at a substantial
> fraction of c, with observers able to time flashes from lightning bolts
> as a train passes an embankment aren't real.
>
>> But in such a dark and gravity free inertial frame, you have abolutely
>> nothing, which could eventually help you to measure absolute velocity.
>
> And Einstein doesn't try to use any absolute velocity. He says simply
> here's a frame where the equations of Newton's mechanics hold good. Are
> you going to complain that Einstein didn't discuss moving objects around
> and accelerating them to test Newton's mechanics?
>>
>> In that scenario you always need something, where you could base your
>> position vectors on.
>
> You, the observer, say "Here's the origin".

That would be actually correct, but was not, what Einstein said.

I personally use a concept I call 'subjectivism', which states, that all 
observers would naturally take the own position and base observations 
upon that.

But the concept of Einstein's SRT didn't do that. Instead, the 
'stationary' frame was 'defined' as one, where the equations of Newton's 
mechanics hold good.

The equations of Newton were actually not developed for such a scenario, 
because Newton lived on planet Earth, where we have gravity and all sort 
of other things, which we do not find in inertial frames of reference.

Therefore Einstein's stationary system were undefined, because he didn't 
write, in respect to what they were stationary.

He couldn't actually do, because this would require infinite regress of 
references.

In the end 'stationary' remains undefined entirely, which would also 
include velocity v and also the term 'space'.

That is quite unfortunate, because velocity plays a mayor role in SRT.

>>
>> You could place a 'buoy' somewhere as reference, but don't know its
>> velocity neither.
>
> Doesn't matter. Observer considers himself stationary and verifies
> Newton's mechanics.
>
> Remember, Einstein was writing for other physicists who understood
> perfectly what the equations of Newton's mechanics hold good means,
> there was no need for him to write another 5000 pages to explain all of
> that.

Sure.

But still 'equations of Newton hold good' would not define 'stationary'.

> You come up with some of the craziest nitpicks, no wonder you found 400+
> "errors" where there are none.


This is not 'nitpick'!

It is absolutely essential in relativity to define relations of objects 
under consideration.

It's simply not allowed to 'reference to nothing' in relativity, because 
the very word 'relative' requires a relation between at least two entities.

>> So, you need another buoy, to reference the position of the first buoy.
>
> What first buoy? Where the observer declares the origin and declares it
> to be stationary? Remember, these are user defined, frames are infinite
> in extent, and can be anywhere the observer wants.

Sure, that would be acceptable, but was not Einstein's setting.

...

TH

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#599796 — Re: Kinetic Energy formula check - a series of short burn rockets, and see how the velocity adds up.

From	Maciej Wozniak <maluwozniak@gmail.com>
Date	2023-01-18 01:17 -0800
Subject	Re: Kinetic Energy formula check - a series of short burn rockets, and see how the velocity adds up.
Message-ID	<41b13e44-1a57-4073-9a82-84f0421dc6b0n@googlegroups.com>
In reply to	#599795

On Wednesday, 18 January 2023 at 09:22:45 UTC+1, Thomas Heger wrote:
> Am 17.01.2023 um 19:04 schrieb Volney: 
> 
> >> Such inertial frames require absense of gravity, which we earthlings 
> >> obviously cannot provide. 
> > 
> > As usual in physics, especially then, things are tested to within an 
> > error limit, where it can be shown the error from the existence of 
> > gravity or whatever is smaller than measurement errors or outcome error. 
> > 
> > Secondly, this is theoretical, it's what happens when there is no 
> > gravity even if such a situation is difficult or impossible to reproduce 
> > in real life. Just like Einstein's trains, moving at a substantial 
> > fraction of c, with observers able to time flashes from lightning bolts 
> > as a train passes an embankment aren't real. 
> > 
> >> But in such a dark and gravity free inertial frame, you have abolutely 
> >> nothing, which could eventually help you to measure absolute velocity. 
> > 
> > And Einstein doesn't try to use any absolute velocity. He says simply 
> > here's a frame where the equations of Newton's mechanics hold good. Are 
> > you going to complain that Einstein didn't discuss moving objects around 
> > and accelerating them to test Newton's mechanics? 
> >> 
> >> In that scenario you always need something, where you could base your 
> >> position vectors on. 
> > 
> > You, the observer, say "Here's the origin".
> That would be actually correct, but was not, what Einstein said. 
> 
> I personally use a concept I call 'subjectivism', which states, that all 
> observers would naturally take the own position and base observations 
> upon that. 

Unfortunately, that's a complete nonsense and
while things are complicated indeed - most observers
are working hard to make their observations
objective.

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#599834 — Re: Kinetic Energy formula check - a series of short burn rockets, and see how the velocity adds up.

From	Volney <volney@invalid.invalid>
Date	2023-01-18 16:33 -0500
Subject	Re: Kinetic Energy formula check - a series of short burn rockets, and see how the velocity adds up.
Message-ID	<tq9ojl$12dv7$1@dont-email.me>
In reply to	#599795

On 1/18/2023 3:22 AM, Thomas Heger wrote:
> Am 17.01.2023 um 19:04 schrieb Volney:
> 
>>> Such inertial frames require absense of gravity, which we earthlings
>>> obviously cannot provide.
>>
>> As usual in physics, especially then, things are tested to within an
>> error limit, where it can be shown the error from the existence of
>> gravity or whatever is smaller than measurement errors or outcome error.
>>
>> Secondly, this is theoretical, it's what happens when there is no
>> gravity even if such a situation is difficult or impossible to reproduce
>> in real life. Just like Einstein's trains, moving at a substantial
>> fraction of c, with observers able to time flashes from lightning bolts
>> as a train passes an embankment aren't real.
>>
>>> But in such a dark and gravity free inertial frame, you have abolutely
>>> nothing, which could eventually help you to measure absolute velocity.
>>
>> And Einstein doesn't try to use any absolute velocity. He says simply
>> here's a frame where the equations of Newton's mechanics hold good. Are
>> you going to complain that Einstein didn't discuss moving objects around
>> and accelerating them to test Newton's mechanics?
>>>
>>> In that scenario you always need something, where you could base your
>>> position vectors on.
>>
>> You, the observer, say "Here's the origin".
> 
> That would be actually correct, but was not, what Einstein said.

He defined a frame in which 'equations of Newton hold good'. Period. He 
defined the origin. No other reference frame necessary.
> 
> I personally use a concept I call 'subjectivism', which states, that all 
> observers would naturally take the own position and base observations 
> upon that.

Thus, Einstein use the perspective of an unnamed observer and called 
this frame "the stationary frame". That's really just a name, it has no 
special features like being "absolutely stationary" in some way.
> 
> But the concept of Einstein's SRT didn't do that. Instead, the 
> 'stationary' frame was 'defined' as one, where the equations of Newton's 
> mechanics hold good.

Exactly. That made it an inertial frame even though he didn't use that 
term. He could then define an origin wherever he wanted as well.
> 
> The equations of Newton were actually not developed for such a scenario, 
> because Newton lived on planet Earth, where we have gravity and all sort 
> of other things, which we do not find in inertial frames of reference.

Newton dealt with the planets and sun in space where there was no air 
resistance, the only gravity was the sun/planets acting on each other 
etc. He was certainly smart enough to know the earth's gravity was 
present when dealing with observations and experiments on earth.
> 
> Therefore Einstein's stationary system were undefined, because he didn't 
> write, in respect to what they were stationary.

"Stationary" was really just a name. It was stationary relative to the 
unnamed observer observing the results of everything. No further 
definitions needed.
> 
> He couldn't actually do, because this would require infinite regress of 
> references.

No need to reference any frame to another to define an inertial frame. 
'where the equations of Newton hold good'
> 
> In the end 'stationary' remains undefined entirely, which would also 
> include velocity v and also the term 'space'.

Wrong conclusion. If this was one of your "400+ imaginary errors", cross 
it off as not an error.
> 
> That is quite unfortunate, because velocity plays a mayor role in SRT.

The velocity of things in this frame, and in other frames he used later.
> 
>>>
>>> You could place a 'buoy' somewhere as reference, but don't know its
>>> velocity neither.
>>
>> Doesn't matter. Observer considers himself stationary and verifies
>> Newton's mechanics.
>>
>> Remember, Einstein was writing for other physicists who understood
>> perfectly what the equations of Newton's mechanics hold good means,
>> there was no need for him to write another 5000 pages to explain all of
>> that.
> 
> Sure.
> 
> But still 'equations of Newton hold good' would not define 'stationary'.

You forget Galileo. There is always something which is stationary in 
this frame. As the paper reads, the observations of the early parts 
which indicates the unnamed observer is stationary in this frame.

Remember, "stationary" is really just a name, as to something moving in 
it, the "stationary" frame is moving in the opposite direction. See Galileo.
> 
>> You come up with some of the craziest nitpicks, no wonder you found 400+
>> "errors" where there are none.
> 
> 
> This is not 'nitpick'!

It most certainly is a nitpick! All that is necessary is to define a 
frame which he did, and add an observer stationary in it.
> 
> It is absolutely essential in relativity to define relations of objects 
> under consideration.

You ignored 'where the equations of Newton hold good' defines inertial, 
and "stationary" can be any such frame he wants.
> 
> It's simply not allowed to 'reference to nothing' in relativity, because 
> the very word 'relative' requires a relation between at least two entities.

So? He introduces moving (in that frame) objects and moving frames later.
> 
>>> So, you need another buoy, to reference the position of the first buoy.
>>
>> What first buoy? Where the observer declares the origin and declares it
>> to be stationary? Remember, these are user defined, frames are infinite
>> in extent, and can be anywhere the observer wants.
> 
> Sure, that would be acceptable, but was not Einstein's setting.

Einstein defines a frame, states 'the equations of Newton hold good' in 
it, names it ("the stationary frame") and implies the observer is 
stationary in it.

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#599859 — Re: Kinetic Energy formula check - a series of short burn rockets, and see how the velocity adds up.

From	Thomas Heger <ttt_heg@web.de>
Date	2023-01-19 09:28 +0100
Subject	Re: Kinetic Energy formula check - a series of short burn rockets, and see how the velocity adds up.
Message-ID	<k2sd92Fud77U1@mid.individual.net>
In reply to	#599834

Am 18.01.2023 um 22:33 schrieb Volney:
> On 1/18/2023 3:22 AM, Thomas Heger wrote:
>> Am 17.01.2023 um 19:04 schrieb Volney:
>>
>>>> Such inertial frames require absense of gravity, which we earthlings
>>>> obviously cannot provide.
>>>
>>> As usual in physics, especially then, things are tested to within an
>>> error limit, where it can be shown the error from the existence of
>>> gravity or whatever is smaller than measurement errors or outcome error.
>>>
>>> Secondly, this is theoretical, it's what happens when there is no
>>> gravity even if such a situation is difficult or impossible to reproduce
>>> in real life. Just like Einstein's trains, moving at a substantial
>>> fraction of c, with observers able to time flashes from lightning bolts
>>> as a train passes an embankment aren't real.
>>>
>>>> But in such a dark and gravity free inertial frame, you have abolutely
>>>> nothing, which could eventually help you to measure absolute velocity.
>>>
>>> And Einstein doesn't try to use any absolute velocity. He says simply
>>> here's a frame where the equations of Newton's mechanics hold good. Are
>>> you going to complain that Einstein didn't discuss moving objects around
>>> and accelerating them to test Newton's mechanics?
>>>>
>>>> In that scenario you always need something, where you could base your
>>>> position vectors on.
>>>
>>> You, the observer, say "Here's the origin".
>>
>> That would be actually correct, but was not, what Einstein said.
>
> He defined a frame in which 'equations of Newton hold good'. Period. He
> defined the origin. No other reference frame necessary.
>>
>> I personally use a concept I call 'subjectivism', which states, that
>> all observers would naturally take the own position and base
>> observations upon that.
>
> Thus, Einstein use the perspective of an unnamed observer and called
> this frame "the stationary frame". That's really just a name, it has no
> special features like being "absolutely stationary" in some way.

What Einstein had in mind is not important, but what he wrote in his text.

I wrote a critique about 'On the electrodynamics of moving bodies' and 
didn't attempt to read his mind in a psychoanalysis.

It is simply irrelevant, what Einstein really wanted, if he didn't write 
that in his paper.

Also subsequent papers are irrellevant for a review, because at the time 
of the article those didn't exist.

That's why I'm allowed to ignore Einstein's real intentions, if they 
were not put into words and those into the text.

Sure, 'the perspective of an unnamed observer' would make sense, but I 
cannot find such a statement in the text.

Contrary to your view, Einstein gave the impression, that he wanted to 
measure velocity against a static and well defined universe.

This was actually a self-contradicting statement, because Einstein also 
wrote, that Newton's absolute space would not exist.

This would require some specualtions about what else would replace 
Newton's universe and 'the perspective of an unnamed observer' would be 
in fact an option, but Einstein left that question to the reader.

And I, as a reader, interpreted Einstein's statements, that he wanted to 
refer to the universe in the sense of the space of fixed stars, but 
erronously also declared that space for noexistent.

This is self-contradicting, because that space of the fixed stars was 
also Newton's 'absolute space', which Einstein said wouldn't exist.

TH

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#599896 — Re: Kinetic Energy formula check - a series of short burn rockets, and see how the velocity adds up.

From	Volney <volney@invalid.invalid>
Date	2023-01-19 16:33 -0500
Subject	Re: Kinetic Energy formula check - a series of short burn rockets, and see how the velocity adds up.
Message-ID	<tqccu9$1n9f5$1@dont-email.me>
In reply to	#599859

On 1/19/2023 3:28 AM, Thomas Heger wrote:
> Am 18.01.2023 um 22:33 schrieb Volney:
>> On 1/18/2023 3:22 AM, Thomas Heger wrote:
>>> Am 17.01.2023 um 19:04 schrieb Volney:
>>>
>>>>> Such inertial frames require absense of gravity, which we earthlings
>>>>> obviously cannot provide.
>>>>
>>>> As usual in physics, especially then, things are tested to within an
>>>> error limit, where it can be shown the error from the existence of
>>>> gravity or whatever is smaller than measurement errors or outcome 
>>>> error.
>>>>
>>>> Secondly, this is theoretical, it's what happens when there is no
>>>> gravity even if such a situation is difficult or impossible to 
>>>> reproduce
>>>> in real life. Just like Einstein's trains, moving at a substantial
>>>> fraction of c, with observers able to time flashes from lightning bolts
>>>> as a train passes an embankment aren't real.
>>>>
>>>>> But in such a dark and gravity free inertial frame, you have abolutely
>>>>> nothing, which could eventually help you to measure absolute velocity.
>>>>
>>>> And Einstein doesn't try to use any absolute velocity. He says simply
>>>> here's a frame where the equations of Newton's mechanics hold good. Are
>>>> you going to complain that Einstein didn't discuss moving objects 
>>>> around
>>>> and accelerating them to test Newton's mechanics?
>>>>>
>>>>> In that scenario you always need something, where you could base your
>>>>> position vectors on.
>>>>
>>>> You, the observer, say "Here's the origin".
>>>
>>> That would be actually correct, but was not, what Einstein said.
>>
>> He defined a frame in which 'equations of Newton hold good'. Period. He
>> defined the origin. No other reference frame necessary.
>>>
>>> I personally use a concept I call 'subjectivism', which states, that
>>> all observers would naturally take the own position and base
>>> observations upon that.
>>
>> Thus, Einstein use the perspective of an unnamed observer and called
>> this frame "the stationary frame". That's really just a name, it has no
>> special features like being "absolutely stationary" in some way.
> 
> What Einstein had in mind is not important, but what he wrote in his text.

But he didn't need to write things his peers were well acquainted with, 
such as the definition of an inertial reference frame.
> 
> I wrote a critique about 'On the electrodynamics of moving bodies' and 
> didn't attempt to read his mind in a psychoanalysis.
> 
> It is simply irrelevant, what Einstein really wanted, if he didn't write 
> that in his paper.

Except things there was no need to write what you claim is needed. 
Remember who his target audience was!
> 
> Also subsequent papers are irrellevant for a review, because at the time 
> of the article those didn't exist.
> 
> That's why I'm allowed to ignore Einstein's real intentions, if they 
> were not put into words and those into the text.

You can't ignore things established in the field of interest. Does he 
need to prove 2+2=4 if he uses that in his paper? How about everything 
Galileo said about inertial frames?
> 
> Sure, 'the perspective of an unnamed observer' would make sense, but I 
> cannot find such a statement in the text.

It wasn't necessary. The first part of his kinematics section explains 
the frame he is going to use.
> 
> Contrary to your view, Einstein gave the impression, that he wanted to 
> measure velocity against a static and well defined universe.

No, he didn't. He used the definition of an inertial frame without 
boring his intended audience (not you) what an inertial frame was.
> 
> This was actually a self-contradicting statement, because Einstein also 
> wrote, that Newton's absolute space would not exist.

Since he wasn't intending to measure any velocity "against a static 
universe", this claim is irrelevant.
> 
> This would require some specualtions about what else would replace 
> Newton's universe and 'the perspective of an unnamed observer' would be 
> in fact an option, but Einstein left that question to the reader.

No need. Once again, his target audience was well aware what a frame is.
> 
> And I, as a reader,

and not part of his intended audience, of course.

> interpreted Einstein's statements, that he wanted to 
> refer to the universe in the sense of the space of fixed stars,

He didn't care how you would misinterpret his statement since he was 
only worried about other physicists, his intended audience.

> but 
> erronously also declared that space for noexistent.

No error since he never claimed to use "the fixed stars" for anything.
> 
> This is self-contradicting, because that space of the fixed stars was 
> also Newton's 'absolute space', which Einstein said wouldn't exist.

And once again, you find a 'fault' based on your own misinterpretation.

How many of your "400+ errors" does this negate? Just one, the fixed 
stars reference, or one for each of my sentences?

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Re: Kinetic Energy formula check - a series of short burn rockets, and see how the velocity adds up.

Contents

#599489 — Re: Kinetic Energy formula check - a series of short burn rockets, and see how the velocity adds up.

#599512

#599513

#599543 — Re: Kinetic Energy formula check - a series of short burn rockets, and see how the velocity adds up.

#599579 — Re: Kinetic Energy formula check - a series of short burn rockets, and see how the velocity adds up.

#599580 — Re: Kinetic Energy formula check - a series of short burn rockets, and see how the velocity adds up.

#599583 — Re: Kinetic Energy formula check - a series of short burn rockets, and see how the velocity adds up.

#599586 — Re: Kinetic Energy formula check - a series of short burn rockets, and see how the velocity adds up.

#599622 — Re: Kinetic Energy formula check - a series of short burn rockets, and see how the velocity adds up.

#599649 — Re: Kinetic Energy formula check - a series of short burn rockets, and see how the velocity adds up.

#599668 — Re: Kinetic Energy formula check - a series of short burn rockets, and see how the velocity adds up.

#599673 — Re: Kinetic Energy formula check - a series of short burn rockets, and see how the velocity adds up.

#599722 — Re: Kinetic Energy formula check - a series of short burn rockets, and see how the velocity adds up.

#599724 — Re: Kinetic Energy formula check - a series of short burn rockets, and see how the velocity adds up.

#599745 — Re: Kinetic Energy formula check - a series of short burn rockets, and see how the velocity adds up.

#599795 — Re: Kinetic Energy formula check - a series of short burn rockets, and see how the velocity adds up.

#599796 — Re: Kinetic Energy formula check - a series of short burn rockets, and see how the velocity adds up.

#599834 — Re: Kinetic Energy formula check - a series of short burn rockets, and see how the velocity adds up.

#599859 — Re: Kinetic Energy formula check - a series of short burn rockets, and see how the velocity adds up.

#599896 — Re: Kinetic Energy formula check - a series of short burn rockets, and see how the velocity adds up.