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Homework Help: Curious force question

  1. Jun 5, 2010 #1
    1. The problem statement, all variables and given/known data
    There might be an obvious answer to this problem, but if two ball for example fall from two different building, one from a tall building and the other from a short building. If the ball from the shorter building hit a barrier, then the ball which fell from the taller building hit the barrier, essentially both balls had the same amount of force exerted on the barriers. (Since f = ma). Then why is it that the ball that fell from the taller building can breakthrough the barrier, while the ball from the shorter building cant.

    Forgive me if the answer is obvious.

    2. Relevant equations

    3. The attempt at a solution
  2. jcsd
  3. Jun 5, 2010 #2


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    Consider conservation of energy, mgh=1/2mv2 where v is the velocity just as it hits the barrier.

    Between the taller and shorter building, which ball will have a higher velocity?

    When you get that, knowing that acceleration is the rate of change of velocity, which one will have a higher acceleration as it is stopped by the barrier?

    F=ma, which one has a higher force?
  4. Jun 5, 2010 #3
    I thought that the acceleration by gravity is constant, and is the same for both balls (9.8 m/s^2)
  5. Jun 5, 2010 #4


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    Yes the acceleration is the same while falling, but when it impacts, that is a different story.
  6. Jun 5, 2010 #5
    Thank you so much, this is starting to make more since.
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