Re: Evil Twin Paradox

On Tue, 7 Aug 2007 20:50:55 -0700, "N:dlzc D:aol T:com \(dlzc\)"
<dlzc@xxxxxxx> wrote:

Dear David:

"David" <dseppala@xxxxxxxxxxxxx> wrote in message
news:djeib3d29fuqhf6jqphp86197mqe13mhbe@xxxxxxxxxx
On Mon, 6 Aug 2007 19:16:07 -0700, "N:dlzc D:aol T:com
\(dlzc\)"
<dlzc@xxxxxxx> wrote:

Dear David:

"David" <dseppala@xxxxxxxxxxxxx> wrote in message
news:u87eb31kdqll2atvpp1bpqtja2i9n3718n@xxxxxxxxxx
...
If the steel wall were not there, either twin could shoot
the other twin as they passed each other. Or if the
steel wall prior to the gap was removed, then the evil
twin could shoot the passing good twin. Or if the
steel wall following the gap was removed, the evil
twin could hit the good twin. But if both sections of
the steel wall are present, then using this length
contraction formula, the evil twin's 100 millimeter
projectile cannot pass through the proton sized gap.
That makes no sense to me.

Fire the projectile "45 degrees" backwards, David.
Then the gap is 10 ly wide to the projectile... which
is the important thing.

In this problem as I stated relative to each spaceship
the projectile travels perpendicular to the ship.

Then the bullet is *much* narrower than the gap in the wall, and
there is no paradox.
That is the rest frame view (good twin's frame). In the moving frame
(the evil twin's frame), the projectile is 100 millimeters wide. It is
not contracted in the x-direction. In the evil twin's frame, the
bullet motion is just in the y direction, so there is a slight
contraction in the y direction. The gap as measured in the evil
twin's frame is
L' = L * (SQRT (1-V**2/c**))
Isn't that correct?
If so, then if V is nearly equal to c, L' can be less than the 100
millimeter wide bullet that the evil twin is shooting. I don't follow
how a 100 millimeter bullet can pass through an opening that is less
than 100 millimeters, unless the bullet has an x component of
velocity, which it doesn't have in the evil twin's frame.

What "makes no sense to you" is that you assumed the bullet was
in the moving ship's frame... with its stationary dimensions,
when you clearly moved it out of the ship's frame.

David A. Smith

.

Relevant Pages

  • Re: Evil Twin Paradox
    ... An evil twin and a good twin are intially in the same reference frame ... extremely long steel wall that extends along the x-axis. ... The length of this gap is L=10 ...
    (sci.physics.relativity)
  • Re: Evil Twin Paradox
    ... An evil twin and a good twin are intially in the same reference frame ... extremely long steel wall that extends along the x-axis. ... The length of this gap is L=10 ...
    (sci.physics.relativity)
  • Re: Evil Twin Paradox
    ... the other twin as they passed each other. ... steel wall prior to the gap was removed, then the evil ...
    (sci.physics.relativity)
  • Re: Evil Twin Paradox
    ... the other twin as they passed each other. ... steel wall prior to the gap was removed, then the evil ...
    (sci.physics.relativity)
  • Re: OBarr comments (globarr):
    ... > Twin A stays at home for 8 years while twin B goes ... then this distance in terms of B's measurement ... the lines are in the frame of B ... > model of the full power of Newtonian physics to ...
    (sci.physics.relativity)
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