In rec.arts.sf.science message <00d45da9-d14d-41e4-82ad-fc6675a1caa3@[EMAIL PROTECTED]
>, Fri, 25 Apr 2008 09:16:59, Brian Davis
<brdavis@[EMAIL PROTECTED]
> posted:
>
>Let’s say you have a person (named, let’s say, “Callie”) standing
in
>the middle of a large airlock (10 [m] long by 3[m] by 3[m]). The bad
>girl opens the large doors at the end, “blowing the lock” (it starts
>at 1 [Atm]). What happens to the helpless heroine?
At worst, approximately, and assuming a heroine of only moderate size
(i.e. not a plug) : since the molecular speed is about the speed of
sound, the energy can only accelerate the gas to about the speed of
sound, 330 m/s. The heroine, being around a thousand times more dense
than air, will be accelerated to about a thousandth of that, around a
foot per second.
A worst case approximation is that a transition between 10^5 Pa and 0 Pa
propagates past her at 330 m/s. So, per square metre, she gets 10^5 N
for a duration of T/330 s, where T is her thickness in metres. Her mean
density will be, of course, 1000 in SI units, so per square metre her
mass is 1000*T; so her change in speed will be 10^5 * T/330 / 1000*T,
which is about 0.3 m/s.
One cannot recommend, for the usual purposes, a heroine who obstructs a
substantial proportion of nine square metres.
--
(c) John Stockton, nr London UK.
*@[EMAIL PROTECTED]
Web <URL:http://www.merlyn.demon.co.uk/>
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