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Re: [Phys-l] Coriolis effect puzzlement



Assuming both air masses to be at the same elevation, and of the same
mass, and assuming we are not at either pole, the air mass closer to the
equator will, on the average, have a greater velocity (since it is
farther from the earth's axis of rotation) hence the net angular
acceleration of the pair of air masses, about a vertical axis through
the midpoint will be counterclockwise, as viewed from above, in the
northern hemisphere, and clockwise, as viewed from above, in the
southern hemisphere.

-----Original Message-----
From: phys-l-bounces@carnot.physics.buffalo.edu [mailto:phys-l-
bounces@carnot.physics.buffalo.edu] On Behalf Of Bob Sciamanda
Sent: Friday, December 02, 2011 9:33 AM
To: Forum for Physics Educators
Subject: Re: [Phys-l] Coriolis effect puzzlement

Typo omission:
Of course, the sentence beginning "In contrast, their momenta . . ."
should read: "In contrast, their angular momenta . . ."

From: Bob Sciamanda
Sent: Friday, December 02, 2011 9:26 AM
To: Forum for Physics Educators
Subject: Re: [Phys-l] Coriolis effect puzzlement
To emphasize the differences between spin/angular momentum calculated
about
the earth's axis vs spin/angular momentum calculated about a real or
gedanken arbitrary space pont (at which a future low pressure center
might
form), consider two air masses located on the same meridian, a meter
or
so
apart apart. In an inertial frame, each has an Easterly directed
velocity,
due to their partaking of the earth's spin. Their angular momenta
relative
to any point on the earth's axis are in the same direction and
completely
additive. In contrast, their momenta relative to a gedanken point
midway
between them (and on their common meridian) are opposed in direction.
The
question is, what happens if a low pressure center develops at the
midpoint,
causing the air masses to move toward that midpoint. The proposed
models
leading to a localized vortex seem to sidestep these complications.