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Homework Help: Magnitude of the initial velocity of projectile

  1. Sep 18, 2011 #1
    A cannon sends a projectile towards a target a distance 1210 m away. The initial velocity makes an angle 26o with the horizontal. The target is hit. The acceleration of gravity is 9.8 m/s2 .
    What is the magnitude of the initial velocity?
    Answer in units of m/s

    y = viy•t +0.5•ay•t2
    vix = vi•cos(Theta)
    vfy = viy + ay*t
    I made a triangle with angle 26o, x=605, then solve for Ymax then got 265.214m. I think the next step is solving for time to get some kind of velocity of X or Y. Is 265m correct, what do I solve for next and how?
    Any suggestions or advice welcome
    1. The problem statement, all variables and given/known data

    2. Relevant equations

    3. The attempt at a solution
  2. jcsd
  3. Sep 18, 2011 #2


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    Homework Helper

    Many texts have a derivation of the range of a projectile in general terms, which express the answer merely in terms of the speed and angle of projection [it only applies for level round]. You can use that to solve directly. The derivation is often presented as part of the proof of desired angle for maximum range.
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