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Homework Help: Projectile Motion, with only Displacement and Angle Known.

  1. May 5, 2009 #1
    1. The problem statement, all variables and given/known data
    A projectile is fired at an angle of 35° and lands 88.5 Meters Down Range.
    Assume no air resistance, and a gravatational acceleration of 9.80665 M/S2

    I can get as far as the trig, but it doesn't seem like there is enough information to find time or velocity.

    Find Initial Velocity Of the Projectile.

    2. Relevant equations
    a = [tex]\frac{(V f - V i) }{ t }[/tex]
    s = V i + [tex]\frac{1}{2}[/tex] at 2

    3. The attempt at a solution

    See Attachment.

    Attached Files:

    Last edited: May 5, 2009
  2. jcsd
  3. May 5, 2009 #2
    Break up the motion into x&y components.

    Since you know the distance, you can write an equation linking Vi and T (total time). Similarly because horizontal speed doesn't change, you can write an equation linking Vi and N=T/2.

    Now, what happens when projectile is halfway there (with respect to the y-component of speed)?
    Last edited: May 5, 2009
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