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What will happen in this situation

  1. Feb 5, 2010 #1
    What will happen if a man jumps inside a train.Will the train move forward and the man land up in different place.Sorry for my bad English.
  2. jcsd
  3. Feb 5, 2010 #2


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    However long it takes for the man to jump, from the ground onto the train, the train will have moved x = vt (where t is that time and v is the velocity of the train). So yeah, the spot will have moved, and it will have moved a lot if the train is going very fast.

    Furthermore, since the train has a lateral velocity and the man does not (i.e. the man does not have any velocity in the direction of the train's velocity), when the man's feet land on the train, they will be pulled with the motion of the train and he may fall over if he doesn't shift his center of gravity appropriately.

    Of course, if you're riding along side the train in a horse and keeping up with it perfectly, then you'll have velocity in the direction of the train, so when you jump it will be as if you jumped from one stationary object to another (ignoring wind and air resistance).
  4. Feb 5, 2010 #3
    Inside a train?
  5. Feb 5, 2010 #4


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    I'm pretty certain the OP is talking about a person that is already riding in the train simply jumping straight up inside the train.

    Not that your examples don't clearly illustrate the principles and answer the question. I wonder if the OP can figure out an answer from what you've already posted.
  6. Feb 5, 2010 #5
    yes,the man is riding train.Should i try this
  7. Feb 5, 2010 #6


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    You have to ask yourself "What is there to slow the man down during his jump?"
    If there is nothing then he will keep travelling at the same speed as the train, landing on the same spot he took off. Newton's First Law
    If the train is open-topped or he's standing on the roof like James Bond, then there may be some drag, caused by his movement (at 60mph) through the air, acting on his body which will slow him down a bit once he is no longer in contact with the train and he may land a short way behind his starting mark on the train.
  8. Feb 5, 2010 #7
    Depends if the train is travelling at a constant velocity and in a straight line.
    If the train is going round a bend to the left when the man jumps he will land to the right.
    The amount of deflection depends depends on how much the train travelled to the left when he is airbourne.
    Likewise he will land in a different spot if the train speeds up or slows down whilst he is airbourne.
  9. Feb 5, 2010 #8
    Yeah, it's a good thing that with constant, linear speed you will fall to the same spot, else imagine the chaos if I jumped or threw something up into the air while inside a passenger jet going a smooth 600mph!
  10. Feb 6, 2010 #9


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