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Re: [Phys-l] Bad physics in National park



Hi,

No, that explanation makes more sense than what they said at the national
park.
What they said at the park was more like "the air that goes over the top of
the
wing has to travel further than the air going under the bottom of the wing.
The
two flows must travel across the wing in the same amount of time.
Therefore,
the top one must travel faster, and since it is travelling faster, the
pressure is lower
above the wing than below. This difference in pressure results in an upward
force
we call "lift", which is what holds up the airplane." I'm paraphrasing from
memory,
but that is as close as I can remember to an exact quote.

Never mind that this "explanation" would imply that planes cannot fly upside
down,
which obviously they can.

That's what bugged me. Not that they invoked Bernoulli at all, but that
they used
this bogus and completely unfounded assertion that the flows take equal time
to
get around the wing to make an argument that had patently false
implications.

Yours,

Don

On Fri, May 22, 2009 at 10:37 AM, Scott Nara <sc.nara@gmail.com> wrote:

I'm curious here and am going to take a moment to make sure my own
understanding is solid. Are you arguing against a Bernoullian perspective
or against their explaination of the Bernoullian perspective? From my
understanding, Bernoulli's principle is applicable here. See the link here
for a far better explaination than I could ever write.

http://www.howeverythingworks.org/page1.php?QNum=1276

Scott Nara
Newport HS Physics
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--
Donald Smith
Guilford College Physics Department
http://www.guilford.edu/physics/dasmith