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Homework Help: Vectors physics

  1. Jul 8, 2015 #1
    A car travels 10 km due EAST then 12. Km NW what is Magnitude of the car's displacement.

    The answer that I got in my book is 8.8
    Could anyone-please-explain ?


    3. The attempt at a solution
    6.6 km
     
  2. jcsd
  3. Jul 8, 2015 #2

    haruspex

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    I got 8.6. We can't tell where your mistake is until you post your working.
     
  4. Jul 8, 2015 #3
    ***I made a mistake .. The answer in the book is 8.6***


    I've just applied Pythagorean theorem to get the answer !!
    144 = 100+X^2

    Could please explain your answer?
     
  5. Jul 8, 2015 #4

    haruspex

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    It is not a right-angled triangle. Do you know a rule for finding the third side of a triangle given two sides and the angle between them?
     
  6. Jul 8, 2015 #5
    Yea..I got the idea

    C^2=a^2+b^2- 2bc COSa
    But still don't know how to get the angle's value
     
  7. Jul 8, 2015 #6

    haruspex

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    Draw yourself a diagram.
     
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