In my animation
https://www.geogebra.org/m/uucnkfhy
there is the chord OD which exerts a blue centripetal force on the
rotating body A and there is an opposite red centrifugal force which is present only in the rotating reference (and not in the inertial one).
Having specified this, is it correct to say that the point of
application of the two opposing forces is point D?
[[Mod. note -- No, not really.
The *centrifugal* "force" acts on A's entire mass, so if we're going to
model it as a force acting at a single point, it (the centrifugal "force") must have A's center of mass as its point of application.
Where the *centripetal* force is applied depends on how A is teathered to
the central point O. E.g. if A is attached to O by a string which connects
to A at point D (the innermost point of A), then that point (D) is where
the centripetal force would be applied. But if (e.g.) the string goes
into a hole drilled into the body A and the string is actually only attached to A at the center of the body A, then the centripetal force would be applied to A there (the center of the body A). And if the centripetal force is supplied by the Newtonian gravity field of a spherical mass located at O, then the point of application is approximately the center of A.
-- jt]]
In my animation
https://www.geogebra.org/m/uucnkfhy
there is the chord OD which exerts a blue centripetal force on the
rotating body A and there is an opposite red centrifugal force which is present only in the rotating reference (and not in the inertial one).
Having specified this, is it correct to say that the point of
application of the two opposing forces is point D?
[[Mod. note -- No, not really.
The *centrifugal* "force" acts on A's entire mass, so if we're going to
model it as a force acting at a single point, it (the centrifugal "force") must have A's center of mass as its point of application.
Where the *centripetal* force is applied depends on how A is teathered to
the central point O. E.g. if A is attached to O by a string which connects to A at point D (the innermost point of A), then that point (D) is where
the centripetal force would be applied. But if (e.g.) the string goes
into a hole drilled into the body A and the string is actually only attached to A at the center of the body A, then the centripetal force would be applied to A there (the center of the body A). And if the centripetal force is supplied by the Newtonian gravity field of a spherical mass located at O, then the point of application is approximately the center of A.
In my animation
https://www.geogebra.org/m/uucnkfhy
there is the chord OD which exerts a blue centripetal force on the
rotating body A and there is an opposite red centrifugal force which is present only in the rotating reference (and not in the inertial one).
Having specified this, is it correct to say that the point of
application of the two opposing forces is point D?
[[Mod. note -- No, not really.
Where the *centripetal* force is applied depends on how A is teathered to
the central point O. E.g. if A is attached to O by a string which connects to A at point D (the innermost point of A), then that point (D) is where
the centripetal force would be applied.
-- jt]]
The simplest way to derive the tides (Earth/Moon only)
is to calculate the combined potential in co-rotating coordinates.
(gravity from Earth and Moon, and centrifugal potential
from the rotation around their common centre of mass)
It is the shortest way to seeing that there must be two tidal bulges,
J. J. Lodder alle ore 18:18:20 del giorno mercoledì ha scritto:
The simplest way to derive the tides (Earth/Moon only)
is to calculate the combined potential in co-rotating coordinates.
(gravity from Earth and Moon, and centrifugal potential
from the rotation around their common centre of mass)
It is the shortest way to seeing that there must be two tidal bulges,
Why does centrifugal force that "appear" ONLY in accelerated references generate bulges that ALSO appear in inertial references?
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