Re: shell theorem


"winston71" <donkey71@xxxxxxxxxxxxx> wrote in message
news:82688d95-e246-47b2-b5c1-13e6a31708c0@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
On Nov 11, 1:48 am, eric gisse <jowr.pi.nos...@xxxxxxxxx> wrote:
On Mon, 10 Nov 2008 15:30:03 -0800 (PST), winston71

<donke...@xxxxxxxxxxxxx> wrote:
Hello,
From wikipedia "1. A spherically symmetric body affects external
objects gravitationally as though all of its mass were concentrated at
a point at its center."

I don't understand the integration. I tried to make a computer
simulation (million random points represent a sphere, there is a test
point outside the sphere, calculate and add each gravity force
vector), but the results came out wrong; total force is minimum when
sphere radius touches test point, and gets stronger as sphere radius
gets smaller (number of sphere points is constant and test point
coordinates is constant). Did anyone try such a simulation and got
good results? Thanks.

Divergence theorem.

Look it up.

Sorry I don't understand that either. At least can you clarify for me
what "spherically symmetric" means?
==========================================
All it means is that for every point within the sphere there is
a corresponding point diametically opposite - a mirror image.
==========================================

Would a mass system of 6 points
which are at the center of a cube's faces be spherically symmetric?
==========================================
Yes... and so would the eight vertices (corners) of the cube.
==========================================
I could add just 6 vectors and see where my simulation went wrong..
==========================================
You could.


.

Relevant Pages

  • Re: magnetic monopoles
    ... > | | into the sphere since they will encounter repulsion ... the mass of the assembled sphere is greater than ... > | | then form a particle of mass. ... I was thinking about an analogy of this B field confinement to ...
    (sci.physics)
  • Re: Question about analysis of Schwarzschild solution on Fo. of Phys. 1988, 18, 6
    ... "On the gravitational field of a sphere of incompressible fluid ... for the mass point. ... The Schwarzschild radius. ...
    (sci.physics.relativity)
  • Re: A Major Design flaw in fusion reactors is holding back progress.
    ... a sphere, this will not be enough to start fusion process. ... The only way to achieve critical mass is by increasing the force ... metals inside that can provide some weak magnetic field around the ... not only provide a force to increase its mass density, ...
    (sci.physics)
  • Re: More on the controversy about the Schwarzschild radius and black holes.
    ... In my reading of his paper, his main assumption is that the point mass ... across the event horizon where the spherical symmetry about the point ... each sphere of symmetry. ... indication that the original problem was in fact ill-defined. ...
    (sci.physics.relativity)
  • Re: a new Yahoo Group for "Dance of the Planets"
    ... > change in density of the mass results in changing the shape of the space ... > wood sphere with a 3 kilogram sphere of Lead or Iron notice how much more ... The Sun's mass and radius are about: ... The density of balsa wood varies from about 5 to 20 pounds per cubic foot. ...
    (sci.astro)