Re: SR cannot determine Contraction

"Dono" <sa_ge@xxxxxxxxxxx> wrote in message
news:8232f6ce-75fb-477e-9a6c-021067923e18@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Simple: if you close both doors simultaneously in the barn frame, you
have trapped the pole inside the barn. This can only happen if the
pole has become physically shorter than the barn.

It has

But this is not what
length contraction is.

Yes .. it is.

So, the thought experiment is self-contradictry.

No .. it isn't

It is a bad way of teaching length contraction, this is all.

Perhaps you were taught badly and that is why you don't understand it.

Sure it is: when compared at rest wrt each other , the pole in the
problem is much larger than the barn.

Yes

Uniform relative motion cannot
make it fit inside rthe closed barn.

Yes it can

This is what I am trying to convey.

And you are wrong

No, let's recap. Length contraction is physical because it is defined
by a physical measurement prescription. There is NO definition of
physical length that bypasses this prescription. This measurement
prescription is as physical as length gets. The fact that it is a
frame-dependent property does NOT imply that there is a physical
process physically altering the rod, any more than the frame
dependence of momentum implies that a different observer adds more
momentum to the object by interacting with it somehow.

Think about what I told you, if you still think that relative motion
can make a longer pole fit inside a shorter barn, we are done,

Indeed, as you are unwilling to listent to those who acutally know what they
are talking about.

there
is nothing more the two of us can discuss.

You really do seem to have some sort of mental block here. Please, go and
read up on length contraction and SR some more .. you've obviously missed
something very basic. Perhaps it was how this was explained to you when you
first learnt it.



.

Relevant Pages

  • Re: SR cannot determine Contraction
    ... The length contraction is a GEOMETRICAL ... PROJECTION that makes the MEASURED length of the pole be shorter than ... the barn with both doors closed. ... individual atoms in the pole frame, ...
    (sci.physics.relativity)
  • Re: SR cannot determine Contraction
    ... The length contraction is a GEOMETRICAL ... PROJECTION that makes the MEASURED length of the pole be shorter than ... the barn with both doors closed. ... You cannot claim that the events do not happen in the pole frame if they happen in the barn frame. ...
    (sci.physics.relativity)
  • Re: Dono not honest enough to admit his mistake?
    ... stuffed up what SR predicts happens wrt length contraction. ... A physically longer pole will not fit into ... toward the barn. ... "Uniform relative motion cannot make a longer object fit inside ...
    (sci.physics.relativity)
  • Re: SR cannot determine Contraction
    ... not shorter than the barn, and you measure it as such. ... If you marked both ends of a pole with light beams, ... door so that it doesn't penetrate clean through at uniform velocity. ... of physics. ...
    (sci.physics.relativity)
  • Re: SR cannot determine Contraction
    ... -This is why one can't close the doors simultaneously in the barn ... frame without hitting the pole. ... very poor illustration for length contraction. ... -This is why, to date, we have no experimental test for length ...
    (sci.physics.relativity)