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Homework Help: Angle of initial velocity

  1. Oct 25, 2007 #1
    1. The problem statement, all variables and given/known data

    At half its maximum height, the speed of a projectile is three-fourth its initial speed. What is the angle of the initial velocity vector with respect to the horizontal

    2. Relevant equations

    any projectile equation

    3. The attempt at a solution

    1. The problem statement, all variables and given/known data

    2. Relevant equations

    3. The attempt at a solution
  2. jcsd
  3. Oct 25, 2007 #2


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    Science Advisor
    Homework Helper

    Split the total speed into a vertical and horizontal component.
    u_horiz = V cos(angle) u_vertical = V sin(angle)
    The horizontal component doesn't change and the vertical component obeys v^2 = u^2 - 2 g h
  4. Oct 25, 2007 #3
    okay so i tried splitting the horizontal and vertical components, but in the end and it doesn't accomplish anything because you get 2 unknown variables, also how would you account for the givens, such as, at half the max height you have 3/4 the initial velocity?

    also i have tried using the equation V^2=V(o)^2 + 2 a x
    from that i set V to (3/4 V(o))
    g to (9.81) and
    x to (x/2)
    in the end that doesnt work out either??
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