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Homework Help: Scalar product of vectors

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

    Let vectorB= 5.45 m at 60°. Let C have the same magnitude as A and a direction angle greater than that of A by 25°. Let B·A = 32.4 m2 and B·C = 35.1 m2. Find the magnitude and direction of A .

    2. Relevant equations


    3. The attempt at a solution
    I just have one problem here. What do I use as theta? do i do cos 60?
    magnitude of b is 5.45 and that of a is unknown but what about the angle?
  2. jcsd
  3. Apr 1, 2012 #2


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    hi madinsane! :smile:
    θ is the angle between the two vectors

    you'll have to give the angle of A a name, ψ say, and then the angle of C is ψ + 25° :wink:
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