a stationary magnet attracts another magnet or a piece of ferromagnetic material. 1) I am trying to quantify (generic formulae) the distance (from the magnet) at which the attracted material starts moving towards the magnet - 2) If I were to try interrupting the attraction at some point after initiation, could a magnetic shield (diversion shield, actually, since the lines of magnetic field must close) be introduced on the path in useful time? What would be the position of its insertion relative to the stationary magnet? Is it possible at all? Thank you in advance.