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Need Help: Projectile Motion Problem

  1. Sep 17, 2009 #1
    1. Assume you are a medieval knight attacking a castle with a cannon. The ball leaves the cannon with a speed of 46.1 m/s. The barrel's angle with respect to the ground is 44.1 degree, and you make a perfect hit on the tyrant's chamber which is at the same level as the cannon's muzzle. What is the time (in s) of flight of the cannon ball?

    2. Y=Yi+Viy(t)-1/2gt^2

    Viy=46.1 m/2
    Y & Yi=0
    Theta Angle=44.1 degree

    I used this equation: Y=Yi+Viy(t)-1/2gt^2

    I drew the x/y coordinate system, right angle and sin/cos to help with solving the problem.
    The online hw site says my answer is wrong. Please help. What am I doing wrong? Is it the equation or my algebra?
  2. jcsd
  3. Sep 17, 2009 #2


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    Homework Helper

    viy is v*sinθ.
  4. Sep 17, 2009 #3
    Thank you! I'll try that.
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