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Simple vector problems (but causing me a headache)

  1. Sep 11, 2009 #1
    1. The problem statement, all variables and given/known data
    For the vectors vector A and vector B in the figure below, use a scale drawing to find the magnitude and direction of the following vector operations. (A = 12.4 m, and B = 18.6 m.)
    (Measure angles counterclockwise from the +x axis) Visual link below

    I was digging a little online and I found another guy with the same problem. He even has the same questions I am stuck on.
    http://www.cramster.com/physics-answers-5-631433-cpi0.aspx

    The only thing different are the numbers I have which are stated above. Someone replied with the answer but I have no idea how he got them.


    2. Relevant equations

    The only ones I have been given are A+ B = The square root of a^2 + b^2
    I also have that Tan(theta) = (ay/ax)


    3. The attempt at a solution

    I got a correct (both the magnitude and angle). However on b I cannot get the angle correct. C and D I am on now. If any help could be provided that would be great. Moreso is how you set up the equations =) I care more on that than the actual answer.
    1. The problem statement, all variables and given/known data



    2. Relevant equations



    3. The attempt at a solution
     
    Last edited by a moderator: Apr 24, 2017
  2. jcsd
  3. Sep 11, 2009 #2
    Just draw the vectors accurately, length and angles, then measure the length and angle of the resultant.
     
  4. Sep 11, 2009 #3

    tiny-tim

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    Science Advisor
    Homework Helper

    Hi Wishingwell! :smile:
    Nooo … the question asks you to "use a scale drawing", not equations. :redface:

    Draw a different https://www.physicsforums.com/library.php?do=view_item&itemid=99" for each part of the question, and just measure the third side. :smile:
     
    Last edited by a moderator: Apr 24, 2017
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