Have a look at http://www.kineticbooks.com/physics/trialpse/13_Gravity%20and%20Orbits/06/sp.html" .adp5025 said:hello all,
I was looking for the equation for the shell therom.
general expression for the magnitude of the gravitational force
but the one were the one sphear is inside the other, such as a person on the earth.
Newton's Shell Theorem is a principle in physics that states that the gravitational force exerted by a spherically symmetric mass distribution is the same as if all of the mass were concentrated at a point at the center of the distribution.
Isaac Newton developed the Shell Theorem as part of his work on gravitation and the laws of motion. He first published the theorem in his book "Philosophiae Naturalis Principia Mathematica" in 1687.
The implications of Newton's Shell Theorem are that the gravitational force on a test particle outside of a spherically symmetric mass distribution is solely determined by the total mass of the distribution and the distance from the center of mass. It also means that the gravitational force inside a spherical shell of mass is zero.
Newton's Shell Theorem is used in many real-world applications, including calculating the gravitational force between celestial bodies and predicting the behavior of objects in orbit around a central mass. It is also used in the study of planetary motion, astrophysics, and other fields of physics.
Yes, there are some limitations to Newton's Shell Theorem. It assumes a spherically symmetric mass distribution and does not account for the effects of relativity. It also does not apply to non-spherical objects or mass distributions with irregular shapes.