Citation needed. Not in any science course I ever took.
The Cause of Gravity
My friend thinks gravity is caused by the Earth spinning, and I think it is caused by the Earth weighing so much we stick to it. Who is right?You are correct. Gravity is caused by the mass of the Earth and has nothing to do with it's spinning.
The spinning of the Earth actually reduces the "gravity" felt by someone at the equator as compared to someone at one of the poles. It is just one of the facts of the Universe that everything that weighs anything, pulls other matter towards it, and the more it weighs, the bigger the pull.
Dr. Eric Christian
(November 2000)
And from Wiki:
The apparent force of gravity on Earth is the resultant (vector sum) of two forces:
[30] (a) The gravitational attraction in accordance with Newton's universal law of gravitation, and (b) the centrifugal force, which results from the choice of an earthbound, rotating frame of reference. The force of gravity is the weakest at the equator because of the centrifugal force caused by the Earth's rotation and because points on the equator are furthest from the center of the Earth. The force of gravity varies with latitude and increases from about 9.780 m/s
2 at the Equator to about 9.832 m/s
2 at the poles.