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Homework Help: Projectile question - X and Y direction

  1. Apr 5, 2012 #1
    A bullet is fired at an angle of 60° with an initial velocity of 200 m/s. How long is the bullet in the air?

    2. Relevant equations

    Vix = Vicosθ
    Viy = Visinθ

    Vfy = Viy + ayΔt
    Xf = xi + VixΔt

    ... Ask for more equations available....
    3. The attempt at a solution

    Vix = 200cos60° = 100m/s
    Viy = 200sin60° = 173.2 m/s

    X variables:
    xi = 0m
    xf = ?
    Δt =?
    Vix = 100m/s

    Y variables:
    Yi = ?
    Yf = 0m
    Δt =?
    Viy = 173.2m/s
    Vfy = ?
    a = -9.8m/s

  2. jcsd
  3. Apr 5, 2012 #2
    Relevant Equation
  4. Apr 5, 2012 #3
    The question is unanswerable, because you are not given knowledge about the initial y-component position of the bullet or the landscape into which the bullet will travel.

    But if we assume your teacher meant to describe a world in which bullets are fired from ground level into landscapes that are perfectly flat, we can proceed. If that is the case, Yi = 0. If you need additional help, just ask for it.
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