Atmospheric stability and lapse rate

"Peter Duniho" writes:

"jim rosinski" wrote:
[...]
You're right about the ****-poor nature of FAA texts though. Not just
the bad meteorological explanations, even their basic physics is wrong.
They blather on about "centrifugal force", which doesn't even exist!

Well, except that unlike the whole lapse rate confusion, the idea of
"centrifugal force" is perfectly valid, depending only on one's frame of
reference, and complained about only by overly pedantic engineers and
laymen.

And physics instructors while grading test answers.

Joe Morris

"Joe Morris" wrote in message
...
"Peter Duniho" writes:

"jim rosinski" wrote:
[...]
You're right about the ****-poor nature of FAA texts though. Not just
the bad meteorological explanations, even their basic physics is wrong.
They blather on about "centrifugal force", which doesn't even exist!

Well, except that unlike the whole lapse rate confusion, the idea of
"centrifugal force" is perfectly valid, depending only on one's frame of
reference, and complained about only by overly pedantic engineers and
laymen.

And physics instructors while grading test answers.

I'd hope that physics instructors would realize that centrifugal force does
exist from the turning object's accelerated reference frame. It's just from
an inertial reference frame that centrifugal force is "fictitious". Either
reference frame is valid; you just have to be careful to specify which one
you're using.

Similarly, from the standpoint of curved spacetime, gravity is a
"fictitious" force. When you cruise near a planet, you just follow a
straight line (through curved spacetime), without being diverted by (or
feeling the influence of) any force. The pressure you feel on the seat of
your pants is analogous to centripetal force--it's the "real" force that
*opposes* the "fictitious" gravitational force.

Still, from our more familiar frame of reference, the force of gravity is
quite real, and we shouldn't object to the FAA's invocation of gravity, or
of centrifugal force.

--Gary