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Homework Help: Problem with vectores

  1. Jan 29, 2010 #1
    Here are three displacements, each in meters:
    d1 = 9i + 5j - 3k
    d2 = -1i + 1j + 3k
    d3 = 4i + 3j + 2k

    What is r = d1 - d2 + d3 ((a), (b) and (c) for i, j and k components respectively)?
    (d) What is the angle between r and the positive z axis?
    (e) What is the component of d1 along the direction of d2?
    (f) What is the component of d1 that is perpendicular to the direction of d2 and in the plane of d1 and d2?

    a) 14i
    b) 7j
    c) -4k
    d) cos-1(-4/sqrt14²+7²+4²) = 104.3
    e) (-9+5-9)/(sqrt(1²+²+3²) = -3.92

    i am having difficulty with e and f i tried e not sure if right but dont understand f

    thanks in advance
    Last edited: Jan 29, 2010
  2. jcsd
  3. Jan 30, 2010 #2


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    f) [(magnitude of d1)^2 - (the component of d1 along the direction of d2)^2]^1/2
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