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Homework Help: Vector components

  1. Oct 22, 2008 #1
    1. The problem statement, all variables and given/known data

    Bob walks 200m south, walks 400m southwest, walks 200m in a direction 30 degrees east of north.
    Use either trig or components to find displacement that will return bob to his starting point by the most direct route.

    2. Relevant equations

    3. The attempt at a solution
    For this problem, I was able to find components for C, which is (200sin30)i + (200cos30)j,
    but how do I find components for B. could somebody show me the steps to getting B components. I can do the rest.
  2. jcsd
  3. Oct 23, 2008 #2
    B components?
    Just picture this its very simple
    200 south
    .../ 400 southwest (assuming 45deg)
    /then 30deg east of north, which i cant draw.

    After explaining this I'm inclined to think that your question is what the angle measure is of 400m southwest, because they ask something else in the latter part of the question I'm inclined to think that they just want you to assume 45deg.
  4. Oct 23, 2008 #3
    Sorry i didnt let you know what B was. B is the 400m southwest. In the solutions manual, they obtained (100) i + (173) j for the 200m in 30 degrees east of north which is equivalent to (200sin30)i + (200cos30)j. But they also had -(283)i - (283)j for 400m southwest. My question, is how is "-(283)i - (283)j" derived. It would be nice if someone could walk me through.
  5. Oct 23, 2008 #4
    Did you draw a picture of B with all the distances and angles marked?

    (If a sketch doesn't help, try a scale drawing, and you'll see what's going on.)
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