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Homework Help: Find direction from three displacement vectors?

  1. Sep 21, 2014 #1
    Consider the three displacement vectors A with arrow = (-4i hat bold − 3j hat bold) m, B with arrow = (6i hat bold − 8j hat bold) m, and C with arrow = (-3i hat bold + 5j hat bold) m. Use the component method to determine the following.

    (a) The magnitude and direction of the vector D arrowbold = A with arrow + B with arrow + C with arrow.
    magnitude = 6.09m

    direction = ___ I came up with 279 degrees but WebAssign said this was the wrong answer - ( tan-1(6/-1) = -80.5 + 360 = 279 degrees )
    -Please let me know what I did wrong. Thanks in advanced!!

    https://s.yimg.com/hd/answers/i/e9b78a68cdc740ec9325bef84b8802c5_A.jpeg?a=answers&mr=0&x=1411359677&s=c34e6240b312c8a385b3b438af3f4519 [Broken]
    Last edited by a moderator: May 7, 2017
  2. jcsd
  3. Sep 21, 2014 #2

    Simon Bridge

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    Science Advisor
    Homework Helper

    Show your working - I think you have misplaced a minus sign.
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