Re: FT: Vortex gravity gradient question

Imre Szabo wrote:

>Does anyone out there have a simple equation (no PDE's or poorly
behaved 
>ODE's) to calculate the pull of a vortex (such as a Black Hole or
Neutron 
>Star) both towards it and around it?  Something in cylindrical or 
>spherical coordinates would be excellent.

F = C * M * m / r^2

where

F = the force on the ship from the vortex (and vice versa of course, but

the vortex is so massive so it won't move much anyway)
C = the gravitational constant (6.67e-11 [N*m^2/kg^2] in SI units)
M = the mass of the vortex
m = the mass of the ship
r = distance from the vortex to the ship

If you're only interested in the acceleration the vortex imposes on the 
ship you use the fact that F = m * a and  get

a = C * M / r^2

If you want to calculate the parabolic or spiral-shaped paths ships
moving 
past the vortex follow, then I'm afraid that you'll have to integrate it
:-/

Regards,

Oerjan
oerjan.ohlson@telia.com

"Life is like a sewer.
  What you get out of it, depends on what you put into it."
-Hen3ry