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Homework Help: Mechanics Projectile Questions

  1. Jan 15, 2008 #1
    1. The problem statement, all variables and given/known data
    At time t = 0 a particle is projected horizontally from a point A with position vector (5i + 30j)m. It passes through point B with position vector (17i +10.4j)m. Find:
    - Its speed of projection
    - Time taken to travel from A to B

    2. Relevant equations

    s = ut + 0.5at²

    v² = u² + 2as

    v = s / t

    a = (v - u) / t

    v = s / t
    3. The attempt at a solution

    Well from A to B the i and j components are


    i can draw a right angled triangle and use pythagerous's thyrom and calculate that the other side is 12.8 (3.s.f) - is that meters?

    Have i gone the right way. I don't know what to do now. Any hints
  2. jcsd
  3. Jan 15, 2008 #2
    Ahh i worked out the verticle component and got t = 2

  4. Jan 15, 2008 #3
    then put this into v = s / t

    v = 6m/s and t = 2s

    yeh :)
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