I am a chemistry student that is trying to calculate the magnetic force on a cylinder due to a gradient produced by sitting in an annulus. The annlus is a cylinder of height h with outer radius ro and inner radius ri. The other cylinder has height h and radius r such that a gap exists with width ri-r. This gap produces a field gradient on the centered magnetic. I am not too sazy with E&M and would appreicated any assistance. Thanks in advance.