Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!watmath!clyde!caip!andromeda!argus!ken
From: ken@argus.UUCP (Kenneth Ng)
Newsgroups: net.cycle,net.auto,net.politics
Subject: Re: re Re Seat belts, Helmets and Freedom of Choice
Message-ID: <414@argus.UUCP>
Date: Thu, 31-Jul-86 07:47:28 EDT
Article-I.D.: argus.414
Posted: Thu Jul 31 07:47:28 1986
Date-Received: Sat, 2-Aug-86 02:19:54 EDT
References: <473@water.UUCP> <2975@pixar>
Organization: NJ Inst of Tech., Newark NJ
Lines: 43
Xref: watmath net.cycle:1886 net.auto:12030 net.politics:17897

In article <2975@pixar>, good@pixar (All of the good ones are taken.) writes:
> In article <473@water.UUCP> kgdykes@watbun.UUCP writes:
> >
> >>From: junk@ur-tut.UUCP (Jan Vandenbrande)
> >When there is impact with the head, the greatest damage comes from
> >SUDDEN DECELERATION of the brain against the skull, helmets don't help.
> 
> This is the second such claim I have seen, and I'd love to have
> someone explain it.  My understanding is that the human head can
> safely decellerate at about 80 gees, and that with a good helmet
> a 200 gee decelleration can be reduced to below 80 for the head.
> In other words, the only thing a helmet really can do is lessen
> the severity of a decelleration.  The relative accelleration of
> the brain vs the skul has got to be proportional to the accelleration
> being applied to the skull by the sidewalk, right?
> 		--Craig
> 		...{ucbvax,sun}!pixar!good
Let's see how well I remember my physics.  The cause of injury appears
to be rapid acceleration (negative).  Acceleration is the change in
speed divided by the distance the change in speed occured.  Therefore
if you stopped something in zero distance, infinite acceleration
occurs.  My guess is that the helmet enlarges the distance in which
the skull decelerates, thus lowering the aceleration.  Lowering the
deceleration of the skull in turn lowers the deceleration of the
brain.  Did I miss anything?

-- 
Kenneth Ng:
Post office: NJIT - CCCC, Newark New Jersey  07102
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