I think I misunderstood what you and Silas were talking about. (Note though that my train thought experiment was about a train with a constant velocity. The billiard ball technique works to detect acceleration of the train even if no rotation is involved.)
I think I misunderstood what you and Silas were talking about. (Note though that my train thought experiment was about a train with a constant velocity. The billiard ball technique works to detect acceleration of the train even if no rotation is involved.)