And what does that theorem say? (In post #1 you mentioned the theorem that deals with the field outside the shell.)Joseph King said:I only know of the one focused inward.
Here's how I would put the two theorems:Joseph King said:Well, basically, it states that if you have an object (ie earth) then the force of gravity is focused at the center. So, if you are underground, the mass above you does not have any gravitational effect on you.
The Shell Theorem states that the gravitational force exerted by a spherical shell on a point mass outside of the shell is the same as if all the mass of the shell was concentrated at its center. This means that the gravitational force inside a hollow sphere is zero.
The Shell Theorem applies to a hollow sphere in that it states that the gravitational force inside the sphere is zero. This is because the mass of the sphere is distributed evenly throughout the shell, resulting in the gravitational forces from each part of the shell cancelling each other out.
The Shell Theorem is significant because it allows for simplified calculations of gravitational forces in situations where a spherical object's mass is distributed evenly throughout its surface. It also helps us understand the behavior of gravity in large-scale systems such as planets and stars.
No, the Shell Theorem also applies to solid spheres. However, the gravitational force inside a solid sphere is not zero, as there is mass present at every point inside the sphere. The Shell Theorem states that the force is the same as if all the mass were concentrated at the center, but it is not zero.
The Shell Theorem is a consequence of Newton's Law of Universal Gravitation. It is a mathematical result that can be derived from the Law of Universal Gravitation and the geometry of a spherical object. The Shell Theorem is a useful tool for applying the Law of Universal Gravitation to specific situations, such as a hollow sphere.