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Homework Help: Two Objects, Constant Acceleration, 1D Forces, Collision Question

  1. Jan 22, 2009 #1
    1. The problem statement, all variables and given/known data

    A ball is dropped from the top of a 50.0 rm m-high cliff. At the same time, a carefully aimed stone is thrown straight up from the bottom of the cliff with a speed of 21.0 m/s. The stone and ball collide part way up.

    2. Relevant equations

    v = v0+at
    x = x0 + v0t + (1/2)at2
    v2 = v20+2a(x- x0)

    3. The attempt at a solution

    Two objects, each with different components of one-dimensional motion. The two objects will share a common impact time because they are put into motion at the same time. I have tried solving for time and setting the equations equal to each other, but this yields no result because when I arrange the quadratic formula it evaluates to y = 0, which doesn't make sense. I don't need explicit help (although I don't mind, I just hate typing this out so I don't expect people trying to help me to), I just need a direction to take this problem.

  2. jcsd
  3. Jan 22, 2009 #2


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    Homework Helper

    What is the question?
  4. Jan 22, 2009 #3


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    Homework Helper

    If they collide there are two things that must be equal.

    Time. and Height.
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