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santistebanc
Does the centrifugal force of Earth rotating around its axis reduces somehow the gravitational force of it? I mean would gravity feel stronger if Earth weren't rotating?
The centripetal force an object feels due to the rotation of the earth about its axis varies with its latitude and points towards the rotation axis; the gravitational force follows the universal law of gravitation, and points towards the center of mass. These vectors add to give you your apparent gravitational force. In your rotating reference frame, you feel both forces as a centrifugal force
On earth, the difference at the equator is less than 1%. On Jupiter it's considerably more and causes the equatorial bulge. The difference between the apparent gravity at the pole and at the equator is something like 20%. Even more fun: since the centripetal force is perpendicular to the axis of rotation, and the gravity is along the radius, the apparent gravity is not parallel to the real gravity.
woow, then how fast is Earth to rotate in order to have moon's gravity on its equator? would it be possible to have zero gravity if it rotated real fast?
I figure it earth rotated fast enough it could negate the effect of gravity, don't know how fast it'd have to go, guessing pretty quick. Otherwise, were it at a standstill the force of gravity would be constant depending on height above sea level (and negligably overhead celestial objects)