The figure shows two cases of conservation of momentum (I think). In case A we have a magnet and a ball bearing just sitting on the table. We bring another ball bearing close to the magnet. The bearing is grabbed by the magnetic force. In case B, we add another bearing, number 3 as shown. Now when the bearing 1 is brought to the magnet, bearing 3 will shoot away from bearing 2 with a large velocity. My question is where does the energy come from in case B that causes the bearing 3 to shoot away so fast. Is the residual field of the magnet reduced?