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Homework Help: Motion in 2-dim, vectors

  1. Feb 7, 2012 #1
    1. The problem statement, all variables and given/known data

    The site from which an airplane takes off if the origin. The x-axis points east, the y-axis points straight up. The position and velocity vectors of the plane at a later time are given by:
    r=(1.61*10^2i) m and v =+100i m/s
    The plane most likely is____

    a) ascending b) descending c) just touching down d) in level flight in the air e) taking off

    2. Relevant equations

    3. The attempt at a solution

    Thought I could exclude C because it's greater than 0, but j isn't give and j could be 0. No idea what the correct answer is.
  2. jcsd
  3. Feb 7, 2012 #2


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    Staff: Mentor

    Think about what the position and velocity vectors of the airplane would look like for each of the five answers to the multiple choice. There's no need to get all quantitative and do calculations; it's enough to just think about what it would mean if each of the i and j components were positive, zero, or negative.
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