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Homework Help: Difficult Projectile Motion Problem

  1. Oct 5, 2009 #1
    1. The problem statement, all variables and given/known data
    A player hits a ball 45º above the horizontal 1.3m above the ground. It clears a 3m wall 130m away. What was the initial velocity?

    2. Relevant equations

    3. The attempt at a solution

    Normally projectile motion problems don't give me much trouble, but in this instance I'm not given the initial velocity and hence I cannot find the horizontal or vertical components of the velocity. It is 45º, so my thought was to find an equation in which the v_x=v_y, but nothing comes to mind.

    The answer in the book is supposedly 36m/s, working backwards gives me a horizontal/vertical velocity of 25.45m/s. I can find the total time of the trip and the total horizontal distance (at a height of 1.3m) but from there I am trumped to find anything remotely similar for the other equation.
  2. jcsd
  3. Oct 5, 2009 #2
    Just had an epiphany

    I think the 3m/130m height away is the vertex or maximum height

    gonna try that out

    edit: i don't think so... 100% stumped
    Last edited: Oct 5, 2009
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