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Homework Help: Another Addition of Vectors question.

  1. Dec 17, 2011 #1
    1. The problem statement, all variables and given/known data

    Sudhir walks 0.40 km in a direction 60.0° west of north, then goes 0.50 km due west. What is his displacement?

    2. Relevant equations

    According to my textbook, the equations are:

    Ax = A cos θ
    Ay = A sin θ
    Bx = B cos θ
    By = B sin θ
    θ = tan-1 opposite side/adjacent side

    Source: http://www.jpopovich.com/file.php/19/phy_chap5.pdf on page 122.

    3. The attempt at a solution

    http://screensnapr.com/e/zuQNvk.png [Broken]

    Click to see full image.

    Both my answers are wrong according to my textbook. Can someone tell me why / explain to me?

    The real answer: 0.87km at 77 degrees west
    Last edited by a moderator: May 5, 2017
  2. jcsd
  3. Dec 17, 2011 #2


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    Homework Helper

    I think you mixed up adding the .5 west. It should go with the west component of the .4, which is the .35 to give you .85.

    Keeping 2 digit accuracy in the work only gives you 1 digit accuracy in the final answer.
  4. Dec 18, 2011 #3
    You seem to have mixed up the x- and y-components for the vector A. You have the correct equations, but you wrote the x-component as the y-component and vice versa.
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