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Homework Help: Simple Vector problem help!

  1. Oct 21, 2009 #1
    1. The problem statement, all variables and given/known data
    So a person walks 10m north, and then walks 18m at a degree of east of south. What is the magnitude and velocity? (Length and angle measure)

    2. Relevant equations
    Law of sines
    Pythagorean theorem

    3. The attempt at a solution
    So I split up this problem into two vectors. The first vector is the guy walking north. So his y=8. His x=0 because he doesn't go anywhere in the x direction. Next I created a triangle to figure out the second vector. We know that the angle at the top of the triangle is 30 degrees. The hypotenuse is 18, and at the left bottom side of the triangle is a right angle (connecting the end of the hypotenuse to the y axis. After doing the law of sines the x2 (x of second vector) is 9. y2=15.59. Now I added the x's to get x total (xt) and the y total (yt). xt=9, yt=23.59. Then with these numbers i created a new triangle and did the inverse tan of 23.59 over 9 to get an angle measure of 69.1. Then pythagorean theorem will get me the hypotenuse of this triangle which is 25.25 and the magnitude of the vector. Am i doing this right??? I just have a feeling I am not. Thank you for all your help :)
  2. jcsd
  3. Oct 21, 2009 #2


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