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From: yzarn@lhdsy1.chevron.com (Philip Yzarn de Louraille)
Newsgroups: rec.skydiving
Subject: Re: Graph of osc'n due to high windforce
Message-ID: <1024@lhdsy1.chevron.com>
Date: 30 Jun 91 03:02:04 GMT
References: <1991Jun21.145113.6028@Stardent.COM> <994@lhdsy1.chevron.com> <1991Jun25.194227.8803@cc.curtin.edu.au>
Organization: Chevron Oil Field Research, La Habra, CA.
Lines: 26

In article <1991Jun25.194227.8803@cc.curtin.edu.au> tcliftonr@cc.curtin.edu.au writes:
>The wind force is 16 N/kg upwards, his/her weight is 9.8 N/kg downwards.
>So the net force is 6 N/kg upwards, giving a net acc'n of 6 m/s2 upwards.
>
Allow me to agree with your numbers since I cannot verify them right
now. First of all, a force is unit of mass * acceleration which is equal
to a Newton or N. Not a N/kg, let us get our units straight, because a
N/kg is a unit of acceleration, not force (I am not being picky, they
are very different concepts.)
Assuming that the net force is 6 N or 6 kg*m/s/s upwards, then the skydiver
is going to slow down. We agree on that.

>Just as I feel my weight reaction push back up on my feet at 9.8 N/kg, 
>or one gee, this re-entering jumper feels 16 N/kg or 1.6 gee pressing
>back up on torso and limbs.  
>
No, this jumper is experiencing .6 g (again, using your numbers) upwards
because it is the *resultant* or *summation* of all the forces (and not
the accelerations) which gives the skydiver his/her motion.
One cannot separate the two forces, they are, in the condition described
above, indessociable (inseparable.)
-- 
  Philip Yzarn de Louraille                 Internet: yzarn@chevron.com
  Research Support Division                 Unix & Open Systems
  Chevron Information & Technology Co.      Tel: (213) 694-9232
  P.O. Box 446, La Habra, CA 90633-0446     Fax: (213) 694-7709