Recent content by ValarDohaeris

  1. V

    Addition of grav potentials / Orbital velocity

    Ah cheers got it now, misread the question was thinking M was the total mass of sphere rather than just the stars contributions.. M(r)_{dm} = 4πρ_0r^2_0r
  2. V

    Addition of grav potentials / Orbital velocity

    I integrated betwee r0 and 0 and got. M(r) = 4∏ρ0r30 v2 = GM/r Not sure where to go from here to get the second term.
  3. V

    Addition of grav potentials / Orbital velocity

    The Attempt at a Solution I think I may of been too general with the volume in finding M_0 I'm assuming r_0 = r_M although I'm not sure why different notation is used thougj http://imageshack.us/photo/my-images/3/gravscan.jpg/