The force on the ball depends upon the material (it's magnetic permeability) - do you mean that it is a ferromagnetic material (soft iron, iron nickel, etc), or that the ball is an actual magnet?
It'll have to be an air core (since something will be inside it) and inside will be a Neodymium N48 nickel-plated quarter-inch diameter ball, so it's an actual magnet.
I apologize if I missed something, but I can't find what I need in those articles. I'm looking for how to calculate the force, in Newtons, on an object with known permeability within the solenoid caused by the known magnetic field. I greatly appreciate any help you can offer.