SpaceBanter.com - View Single Post - Quantitative Prediction of a Measurable Quantity

Pentcho

Can you please stop for a bit, and write something about my equation.
Does it make sense ?

On Aug 14, 12:45 am, Pentcho Valev wrote:
On Aug 13, 4:17 pm, PD wrote:

On Aug 13, 9:12 am, Pentcho Valev wrote:

On Aug 13, 3:47 pm, PD wrote:

On Aug 13, 8:25 am, Pentcho Valev wrote:

On Aug 13, 2:30 pm, PD wrote in
sci.physics.relativity:

I think you don't know what a physical theory is.
Can you please provide a quantitative prediction of a measurable
quantity?
That's what a physical theory does.

PD

Clever Draper, I have aleady asked you and you did reply I must admit
but I cannot remember your answer so again: What is the quantitative
prediction, Clever Draper, for the length of a 80m long pole safely
trapped inside a 40m long barn, provided your brothers have forgotten
to reopen the doors of the barn "pretty quickly" and the doors don't
break:

Well, of course the quantitative prediction depends on the relative
speed between the pole and the barn, but there certainly is a value of
the relative speed for which the quantitative prediction for the
length of the pole in the barn frame is not 80m but 39m. (The "80m"
you referred to in your question above is an adjective that presumably
applies in the rest frame of the pole, but does not apply in any other
frame.) This yields the qualitative prediction that the doors can be
closed briefly without touching either end of the pole.

Now, no one has done this exact experiment with a barn and a pole,
though there is a clearly a quantitative prediction. Fortunately, the
theory makes a number of other quantitative predictions which HAVE
been tested -- and confirmed -- in experiment.

The role of the barn-and-pole puzzle is then left, not as an
experimental prediction, but as a teaching exercise -- which
apparently still leaves some Bulgarians addled.

http://www.math.ucr.edu/home/baez/ph...barn_pole.html
"These are the props. You own a barn, 40m long, with automatic doors
at either end, that can be opened and closed simultaneously by a
switch. You also have a pole, 80m long, which of course won't fit in
the barn....So, as the pole passes through the barn, there is an
instant when it is completely within the barn. At that instant, you
close both doors simultaneously, with your switch. Of course, you open
them again pretty quickly, but at least momentarily you had the
contracted pole shut up in your barn."

Bravo Clever Draper! Bulgarians are by no means addled - rather, they
adore you and your answers. Just a small elaboration: "the
quantitative prediction for the length of the pole in the barn frame
is not 80m but 39m" but then, when the pole is safely trapped inside
the barn, it will try to restore its proper length (which is 80m).

Why would it do that? The doors NEVER touch the ends of the pole.
If you have a fly that flies into a barn and you shut the doors of the
barn, the fly continues to fly around inside the barn, and when you
open the doors of the barn, the fly flies out.
Why are you assuming the pole is brought to rest inside the barn? You
perhaps misunderstand the barn and pole puzzle as it is commonly
taught.

The pole enters the barn.
The doors are briefly shut, while the pole is *still* moving at
constant velocity.
The doors never touch the ends of the pole.
Before the pole reaches the far door, the doors are opened back up.
The pole continues to fly out, never having changed speed.

You mean ALL THIS TIME you've been flummoxed by the barn and pole
paradox BECAUSE YOU CAN'T READ???

But
since the doors of the barn don't break, the pole will be able to
restore only 1 meter so when Clever Draper goes and measures the
length of the trapped pole, Clever Draper clearly sees a 40m long
pole, perhaps a few centimetres longer if the doors are slightly
deformed. Is this realistic, Clever Draper? A 40m long pole and that's
it?

Clever Draper, Cleverest Draper, why these zombie tricks again? Look
at my initial question and you will see the phrase:

"....provided your brothers have forgotten to reopen the doors of the
barn "pretty quickly"...."

In other words Clever Draper, your brothers always camouflage the
idiotic implication of Divine Albert's Divine Theory by reopening the
doors of the barn "pretty quickly" but only once they failed to do so
and now we are discussing the consequences of their failure. How long
is the pole trapped and immobile inside the barn, Clever Draper?

Pentcho Valev