A question I'm embarrased to ask - earth's spin

C-force is a force, not a motion or change of motion.
True, there will be some "deflection" if the force is not
resisted, but often it is resisted, so there will be a
force, but no deflection.

Exactly. When I said "deflection" I was referring to an unresisted
case. It is easier to visualize. Once visualized, it becomes evident
that resistance will generate a force, and that incomplete resistance
will still leave some deflection (which is what causes the winds to
circulate the way they do).

C-force depends only on the
velocity vector of the moving item...

but what I'll call Coriolis deflection (the result of unresisted
coriolis effect) depends on the time that has transpired. Consider the
cannon at the North pole again. When the Acme RapidFire SuperSonic
HighSpeed cannonball reaches the equator, it will be moving with next to
no angular velocity (around the polar axis) while the ground underneath
will be moving at a thousand miles an hour (eastward). Since the
cannonball got there in LicketySplit time, the earth will not have had
much time to move much, and the path would be pretty straight if drawn
on the globe. This is easy to visualize, which is why I used it as an
example. Now, resisted, there would have been a large force for a short
time, therefore a high acceleration. I believe this is what you are
referring to.

However, if we put a SlugBall (tm) into that cannon, and it took a good
six hours to get to the equator, and we also neglected air friction, the
SlugBall, taking the very same (with respect to the fixed stars) path,
would find that the earth has rotated a quarter of the way around in
that time. It would have hit the Amazon, now it hits the Sahara. When
drawn on the earth, the path is curved in a major way. This is also
easy to visualize. At slower speeds, the deflection is much greater.
Granted, if resisted, there'd be the same delta vee, over a much longer
time, and therefore a smaller force. But it's a bigger deflection on
the map unresisted.

This is why I was careful to say "coriolis effect" and not "coriolis
force". Perhaps that's a bit sloppy.

Coriolis force is quite simply
twice the vector cross product of the spin vector and the
velocity vector.

Most people equate "cross product" with "teenager".

If you are
flying East at the equator and reach your orbital speed the
Coriolis force will equal the force of gravity and be
upwardly directed.

True, and in any case lessens the force on the wings, and thus the drag.
I hadn't put that much together as being the same coriolis force. It
could be said that coriolis force keeps a satellite in orbit. I think
doing so however would tend to muddy the water before clearing it up.

And the coriolis force on a southbound cannonball at the equator should
be zero. Yet that is where you'd see the greatest coriolis effect
("unresisted deflection"). You'd be going south by the fixed stars, and
the earth would be slipping past you right to left at a thousand miles
an hour.

Jose
--
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what they are." - (mike).
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