Re: answer to YBM's bell problem

rbwinn a écrit :
On Sep 9, 12:46�pm, YBM <ybm...@xxxxxxxx> wrote:
rbwinn a �crit :

YBM proposed the folowing problem.
Here it is :





two light rays are emitted from (-a,0,0) and (a,0,0) (a>0)
at the same time in A in the direction of the origine
of A (so velocities are respectively (c,0,0) and (-c,0,0).
When both arrive at O it makes a bell ring.
Try to seriously answer these questions :
In frame A and in frame B :
- What are the coordinates of both photons at a
� given time ?
- What are the coordinates of the event "the bell ring"
� in A and in B.
At every step explain why you choose t, t' or n' (and
which n') as time coordinate.
�... Since he did not
specify whether the bell was at the origin of A or the origin of B, we
will work the problem with the bell at the origin of A. �
At least you've guess one thing right in your life. The bell is
at rest in A frame. You seem to have guess right, as well, that
both light rays were emitted � t=t'=0.

In A, the
light is emitted at x=a and x=(-a).
�In B the light is emitted at
x'=a and x'=(-a). �
It is what you'd get if you use Galilean transformations.

Light emitted at -a has a velocity of c relative
to both frames of reference. �
This is NOT what you'd get if you use Galilean transformations.

Light emitted at a has a velocity of -c
This is NOT what you'd get if you use Galilean transformations.

relative to both frames of reference. �If the bell is at the origin of
A, it will ring when t=a/c.
� �The mathematics for this is, for the light from -a, x1=-a, x2=0
� � � � x2-x1 = �0-(-a) = a
� � � � x=wt=ct =a
� � � � t=a/c
� � For the light from a, x1=a, x2=0 � w=(-c)
� � � � x2-x1= 0 - a
� � � � �x=wt=(-c)t = -a
� � � � �t=a/c
You forget to say that this is in frame A. Then this is ok.

Light from both directions reaches the bell at a time of a/c, and the
bell rings.
�To determine what time a clock in B reads when the bell rings,
� � � � � � n'= t(1-v/w)
� � � � � � �n'=a/c(1-v/c)
You have a very fancy way to use your own "thoery". There is
TWO light rays. One with velocity -c, the other one with
velocity c. Here you only use w=c. Is there something
special with the light ray comming from (-a,0,0) ? Moreover
if you compute the speed of the other light ray, using
n'=a/c(1-v/c), you won't get c.
That is correct. That is why the equation says w instead of c.
For light from the other direction, you get -c for the velocity of the
light.
Do you see why I asked you a problem with *two* light rays to consider ?
Well, I can consider both light rays. What is the problem you see?

For a single case, you have two clocks, each of them tweaked in
order to give a specific result about part of the experiment. This
has nothing to do with what both Galilean and Lorentz transformations
consider : a simple clock, running well, at rest in B.

To point out that this force you to arbitrarely choice one of
the rays to setup your "slower clocks", but then the other light
ray won't propagate at c.
The other light ray has a velocity of -c. That is what w means.
If you had followed your *own words* you'd have used w=c
for the ray emitted at (-a,0,0), giving for you "slower
clock" : n'=a/c(1-v/c), then when considering the
light ray emitted at (a,0,0), at velocity -w you'd have
used n'=a/c(1+v/c).
Yes, that is correct.

Then you'd have found that your "theory" does not
provite a unique time for a single event... In other
words, what is an event in frame B, is *two* event
in frame B : both light rays, according to you theory,
do not arrive on the bell at the time... so the bell
does not ring in B. But it rings in A : contradiction !
The time n' in B is saying that the two light rays meet at the origin
of B

There is no "time n'" in B in this case : there is two candidates.
Which one do you select ? Why ?

, not at the origin of A.

Beside not being what you formulas says, this is absurd : now,
according to you, the two light rays are meeting on the bell
for observers in A, but elsewhere for observers in B. Note that,
then, the bell won't ring neither.
How absurd are you going to be ?

That being the case, they cannot be
used to compute the time when the bell rings. The bell rings when the
light meets at the origin of A according to the time in A, which is
t=a/c. The way this relates to time in B is that B has traveled a
distance of vt, and the origin of B is a distance of vt from the
origin of A when the bell rings. So the bell rings in B when the
origin of B is a distance of vt from the origin of A, not when an
observer in A thinks light has reached somewhere. The light is not
controlled by observers.

Is it a kind of random poetry ? Did you realize that as seen in B,
according to your theory and the variant (without formulas) you
just introduced, the bell doesn't ring ?

It is indeed not in SR and GR, in you "theory" it is worse : what
happens differs according moving observers, clocks differs according
to the event an observer consider, and so on ...

There is no such absurdities in SR : for SR, the bell
rings in both frames... It just happens that in frame
B they were emitted at coordinates
(-a/sqrt(1-v^2/c^2),0,0) at time va/(c^2*sqrt(1-v^2/c^2))
for the "left" light ray, and :
(a/sqrt(1-v^2/c^2),0,0) at time -va/(c^2*sqrt(1-v^2/c^2))

Next time you'll pretend I've proven something, please
don't lie and write that I've proven Robert Winn's modified
"Galilean Transformation" to be absurd.- Hide quoted text -

Well, it would have taken me years to have gotten n' from the
equations you derived it from. I have to give you credit for it.

I just reverse two of the meaningless I provide in order to get
the value of n' you didn't provide in a specific case. If you
are so dumb that it would have taken years for you to get your
own meaningless equations from a equivalent form you just provide,
why don't you ask yourself a simple question : "Is it surprising
that everyone says me I don't understand equations of motion,
Galilean transformations, Lorentz transformations, ... ?"

So
you do not think the length contraction is an absurdity. I think the
length contraction is an absurdity.

Given that what you've proposed for 11 years has now being proven
completely absurd, could you go on and try to understand what
lenght contraction is ? Feel free to ask here for help. But
- please - read the numerous FAQ and posts in the archive about
this issue first.

And I strongly insist :

Next time you'll pretend I've proven something, please
don't lie and write that I've proven Robert Winn's modified
"Galilean Transformation" to be absurd.
.

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