Re: Flying High ?

Date:         03 Mar 98 03:12:50 
From:         mweber@t140.aone.net.au (James Matthew Weber)
Organization: GoodNet
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On 19 Feb 98 01:34:26 , Chris Pitzel <chris.pitzel@usask.ca> wrote:
>If you were to measure your weight on an aircraft at FL400 and your
>weight at sea level, you would find that you would weigh less at
>altitude.  For example, I weigh roughly 130 pounds at sea level, yet I
>would only weigh perhaps 110 pounds at 40k feet.  There are formulas to
>determine this which can be derived from the relationship:
>
>	F = G*m1*m2/r^2

The reduction in F is trivial, in fact the radius of the earth is
substantally higher at the equator than it is at the poles, far more
than the mere 8 miles that 40,000 feet represents. The difference in
weight between sea level and 40,000 feet . If you take the radius of
the earth to be about 4000 miles, you can work out that the
differerence in F is about .2%.  Your 130 pounds at sea level will
weight 129.7 pounds at 40,000 feet.  This is simply not a significant
factor.