HW5
          (Extra credit) A member of the physics faculty at the University of Florida, Prof X. recounts the story of how his physics teacher explained that magnets always had a north and south pole, and that you could determine where they were on a sample magnet by taking a standard bar magnet with N and S labelled, and holding the N end up to both ends of the sample magnet.   The N end of the standard bar would then be attracted to the S end of the sample magnet and repelled from the N end, thus determining the N and S poles of the sample.  The mischievous young X. used some standard household materials and some standard bar magnets, then presented his teacher with a sample magnet which,
upon testing, was seen to have two N poles, puzzling the teacher mightily.  What had he done?  Was the teacher very bright?