A disc magnet has its north and south poles on its faces. To achieve levitation of a model maglev train, how should the magnets be arranged on the train and track?

• A. flat, so that the north pole of the magnets on the train points up and the north poles of the magnets on the track point down
• B. flat, so that the north pole of the magnets on the train point up and the north poles of the magnets on the track point up
• C. on edge, so that the north poles of the magnets on the train point to the front and the north poles of the magnets on the track point toward the rear
• D. on edge, so that the north pole of each magnet on the train and on the track point toward the rear of the train

Answer: (A)