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Homework Help: Magnitude and Direction

  1. Sep 17, 2008 #1
    Last edited by a moderator: May 3, 2017
  2. jcsd
  3. Sep 17, 2008 #2
    Start out by finding the x and y components of the two vectors shown.
  4. Sep 17, 2008 #3
    F1 = 120cos(60*) = 60
    120sin(60*) = 103.9
    x and y = (60,103.9)

    F2 = -75cos(75*) or is it -75cos(15*)? = -19 or -72.4
    75sin(75*) or 75sin(15*) = 72.4 or 19
    x and y = (-19,72.4) or is is it (-72.4, 19)
  5. Sep 17, 2008 #4
    Either angle (75* or 15*) would work, the problem arises when you apply the trig functions to find the components. For example, look at how the the cosine function is defined: cos(theta) = adj/hyp. In your second answer for the x component of F2, you are saying that the leg adjacent to the angle is on the x axis, when in reality it is along the y axis according to the definition of cosine.
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