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Slope/Hill velocity effect

  1. Apr 23, 2009 #1
    Lets say two wagons is approaching a hill/slope which ends up at the exact same height as before the slope/hill. The wagons are identical and are traveling at the same velocity at point A (approaching the hill/slope). And the hill's/slope's shape is exactly the same but inverted.

    Which if any, of the wagons reaches point B first, and which has the highest velocity at that point.

    To me it seams logical that its the same for both wagons but as I remember it from a physics assignment in school a couple of years ago that isn't the case and the wagons time/velocity are different at point B.

    If so, why?
     

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  3. Apr 23, 2009 #2

    HallsofIvy

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    Looking at it in terms of "conservation of energy it is clear that the velocity of the two wagons will be the same at B- they are both at the same height they were before so have the same potential enter, thus the same kinetic energy and so the same velocity.

    However, the lower wagon will have increased decreased potential energy, so increased kinetic energy and thus higher velocity while going through the while the first wagon has increased potential energy, so decreased kinetic energy and thus lower velocity while going over the hill. Afterwards, they will have the same velocity but the lower wagon will get to point B slightly sooner than the first wagon.
     
  4. Apr 23, 2009 #3
    Thank you. It's nice too I still remember something at least. And that both that me and my colleague was "right" in a way.
     
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