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Homework Help: Height of the two balls collision

  1. Feb 4, 2010 #1
    1. The problem statement, all variables and given/known data
    Ball A is dropped from the top of a building of height 'h' at the same instant that Ball B is thrown vertically upward from the ground. When the balls collide, they are moving in opposite directions, and the speed of A is twice the speed of B. At what height does the collision occur?

    2. Relevant equations
    x1=x0 + Vot - 1/2gt^2

    I've been having a hard time with this. I just cant get it.
  2. jcsd
  3. Feb 7, 2010 #2


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    Staff: Mentor

    Usually you will use "y" for the vertical position variable (small point, but confusing otherwise).

    Write an equation for the position of each ball as a function of time, and set them equal (that's where they collide in the y axis)... Please show us your work so that we can help you.
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