I am a mechanical engineering student so dont have experience in specifying magnets and or using them. So its out of my comfort zone. I currently have a U shaped structure holding two large permanent magnets apart at either end. The magnets will need to be 200x200x40 in size and the gap is going to about 250mm. How do i calculate the force that will be exerted on the structure given typical specs from suppliers. What specs will i need and formulae? I've had a look at literature and it seems to have been reading and derived the the classical formulae for force between magnets. F=6k(qm*qm'*L2)/r2 and i Know that Mm = qmL Is this the correct formula to use? If soo, I can't seem to find the variables to fit into the equation from typical data given from magnet suppliers.