"Nav" wrote:

What happens if omega=0 and the body is in free fall? Are there
still two tides?


If the rotation of the moon was stopped, and the moon and the earth
was "falling" towards each other, there would still be two bulges, as
far as I can figure out.

(You wouldn't have any centrifugal powers, but you would have an
acceleration.)

Peter S/Y Anicula


"Nav" wrote:

What happens if omega=0 and the body is in free fall? Are there
still two tides?

Anyway, there's no point to my constantly repeating myself so we'll
just
have to agree to disagree. In case anyone else is interested, here's
a
quote from a teaching site that explains it all quite simply.

http://ijolite.geology.uiuc.edu/04Sp...tes/Lect29.pdf

" TIDES
Periodic rise and fall of water level along coastlines related to
the
phases of the Moon.
One cause: The moon's gravity.
BUT...If this were the only cause, we would have only one high
tide
per day (i.e., we would have
high tide when we are position closest to the moon). However,
there
are often two high tides and
two low tides per day- why?
The other issue: Centrifugal/centripetal forces.
1. The moon orbits around the earth, and this makes the earth
"wobble". More precisely, the earth
and moon both orbit around their center of mass.
Analogy: Imagine a large adult and small child holding hands and
spinning around. The
child spins in a wide circle, but the adult also moves in a
circle,
albeit a smaller one
because the adult is so much heavier.
2. Because the earth is orbiting (moving a circle slightly) there
is a
"centrifugal force". Or, more
accurately, there is a centripetal force required to move the
earth in
that orbit.
Cause for Tides: imbalance of two forces:
1. G = Gravitational attraction between Earth and the Moon (and
Sun).
2. C = Centripetal force = Force needed to make the Earth revolve
around the center of mass
(center of gravity) of the Earth-Moon system.
Here's the imbalance part:
1. Gravity from Moon stronger on side facing moon, weaker on the
side
away from it
2. Centripetal force is the same everywhere on earth
3. G and C are exactly balanced at center of the earth
4. They are not balanced in other places that are closer to moon
or
farther away from it
. Example: On the side away from the moon, the centripetal force
needed to keep the
ocean water in its orbit is greater than the gravitational force
from
the moon
. Net result is like a force away from the moon (a centrifugal
"force")
5. So wherever C and G do not balance, there is force that is
large
enough to make water
flow
6. Water flows and forms tidal bulges "


Cheers