Hi Saw this in a Science Centre - There truck on an inclined slope. At the head of the truck is a magnet. the end of the track is a wire with electric current (DC i think). As the truck is released, the wire moves a little away from the truck. The truck gets near the wire but not touching it and then moves backwards. the motion repeats. Why? I think it has something to do with the wire becoming a magenet and repel the truck-but how the whole thing work? truck (magnet) ----> wire attached to battery. Thanks for the explanation. Cheers!