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Inside a Train

  1. Aug 11, 2010 #1
    I was watching I LOVE LUCY and they were traveling on a train. Lucy kept pulling the emergency lever for various reasons. One of the times, Ricky was taking a leap up into the air and when the train stopped, he ran into the wall of the train because he was making the leap but the train stopped.

    According to the laws of physics, would this actually happen?
  2. jcsd
  3. Aug 11, 2010 #2
    If the train stopped while he was still in the air, yes. If we suppose that the train before was going with constant speed than the passengers also go with that speed, so if it starts stopping you have to grab on to something to change your speed too, and if you are in the air at that time the wall will change your speed.
  4. Aug 11, 2010 #3
    But it takes quite a while for a train to stop. A lot longer than the air time of a human leap.
  5. Aug 11, 2010 #4
    Yes you are right although I dont know the maximum deceleration of a train and it depends on many factors I m sure it wouldn't be that dramatic.
  6. Aug 12, 2010 #5
    In case of hard breaking of the vehicle, the passengers will continue their uniform forward motion and hit the front of the vehicle.
    I'm sure you have experienced it yourself, maybe not in a train but in a bus or a car, but it's still the same thing. So I wonder why are you even asking such a trivial thing.

    And it doesn't matter much if you leaped or not. If you are stepped on the floor you will have a better chance of countering the perceived force that pushes you forward, but that force itself will be the same strength in either case. And if it is big enough, even being stepped on the floor won't be much help to you.
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