Help with apparent paradox please?
- From: dunxuk@xxxxxxx
- Date: 13 Apr 2006 12:32:03 -0700
Can anyone help me with this; I'm getting increasingly confused by this
puzzle:
=====
Two carriages rush along together travelling nearly at c. The rear
carriage has a
guardsman at the back that can apply brakes to the rear wheels.
The driver at the front of the front carriage can apply brakes to the
front wheels. All of the other wheels turn freely and both sets of
brakes have exactly the same decelleration affect (they have been
calibrated).
The ticket collector stands in the middle at the joint between the
carriages and sets off a pulse of light. As soon as the guardsman and
driver receive the pulse they slam on their brakes. Unfortunately the
carriages haven't been coupled but luckily the pulse reaches both ends
at precisely the same time and both carriages screech to a halt
together.
Unfortunately the whole incident was observed by a railway inspector
standing some distance away. As the train was nearly at c he saw the
light flash from the middle reaching the guardsman at the rear very
quickly but it took ages to reach the driver at the front as the train
was travelling almost as fast as the light. The net result was the
guardsman at the back received the light pulse and applied the brake
long before the pulse reached the driver and the rear carriage started
braking first. A gap immediately opened between the carriages and the
poor ticket collector fell to a horrible death. The carriages
eventually stopped some distance apart.
Well, did the ticket collector die or not?
=====
Is there an explanation that doesn't involve the fact that trains can't
go that fast etc? This is a genuine request, I'm not trying to make any
statements!
Many thanks everyone!
.
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