Suppose say a person is standing over the moving bike and he jumps while bike is moving, bike will move forward & person will land in same point at which he jumped, relative to earth position (Assuming he wont roll or fall due to unsteady). This is same as expected behaviour.

But if a same person jumps inside a bullet train, He will move forward and land in a point ahead of actual location, relative to earth position.

Why is it so?

  • $\begingroup$ I do not see why you make a difference. When he jumps from the bicycle, he is moving at the speed of the bicycle. Since the jump will take a little time, he will not land at the same place on earth. He will stop moving only when reaching Earth (if he does not fall). Situation is the same as when jumping in the train. The person (assumed to be already in the train) goes at the same speed as the train, and will land at the same spot on the train, and thus at a point ahead on Earth since the train and himself are both moving forward at the same speed. $\endgroup$ – babou Feb 10 '14 at 10:56
  • $\begingroup$ @babou: are you saying that in both scenario person will move ahead from the jumping point, since bike/bicycle are slower in velocity to train, so displacement will lesser & hence I'm not able to observe it??? $\endgroup$ – Mani Feb 10 '14 at 11:05
  • 2
    $\begingroup$ I think you understood me correctly. - - - This is a standard problem in science. When a phenomenon is difficult to observe, people will at first remain unaware of its existence and possibly draw erroneous conclusions which are actually rough approximations corresponding to their rough perception of reality. And it may even happen (actually quite often) that the layman who cannot use the proper means of observation and reasonning will not believe the scientist. $\endgroup$ – babou Feb 10 '14 at 11:18

In both cases, the person who jumps has inertia of motion and hence will land in front wrt the earth's reference frame. It is the same effect which makes you jump forward and keep moving for a while when getting down from a slowing bus/train.


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