A train is approaching you at very high speed as you stand next to the tracks. Just as an observer on the train passes you, you both begin to play the same Beethoven symphony on portable compact disc players.
(a) According to you, whose CD player finishes the symphony first?
(b) What If? According to the observer on the train, whose CD player finishes the symphony first?
(c) Whose CD player really finishes the symphony first?