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Homework Help: Please Help: Finding Scalars from Vectors

  1. Sep 14, 2004 #1
    A=6i-8j m, B= -8i=3j m

    I know how to add and multiply vectors, but how do I find the two scalars of a and b?
    Also, I can’t figure out how to find the unit vector and direction of Resultant Vectors.

    Please Help!


  2. jcsd
  3. Sep 14, 2004 #2
    The "scalar" of a vector I assume you're speaking of the "magnitude" as expressed by the notation |A|. This is similar to finding like the hypotenuse of a triangle.
    For A, if you go 6 units to the right, then 8 units down, how far is your point from the origin? Thats what the magnitude is. If you know basic trig you use the pathagorean theorem to solve for that length.

    A unit vector is just a vector with a magnitude of 1. So it has the same direction as the original vector, which means it has the same ratio of hight to width(i to j). How do you think you could get this vector with magnitude of 1?

    "Reslutant" vector I assume you mean that if you do one and then the other from that point, where are you? So it would be basic "vector addition". If your vectors were just 5i and 19i, and you wanted the resultant, well, take a pencil from the origin 0, and move to the right 5 units, then again 19 units. Now a vector is "how far" and "in what direction". So you would be 5+19 = 24 units, still in the "i" direction, so the resultant = 24i. You can apply this same reasoning to the other vectors.
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