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Homework Help: Body diagonals -- unit vector notation

  1. Oct 23, 2016 #1
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    1. The problem statement, all variables and given/known data

    I'm fully convinced that the zero values make sense, yet they are wrong, can somebody plz explain why is that the case

    4.png

    2. Relevant equations
    N/A

    3. The attempt at a solution
    Attempt in the image above
     
  2. jcsd
  3. Oct 23, 2016 #2

    haruspex

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    (a,0,0) is the bottom, left and front vertex in the diagram, right? Where is the other end of the diagonal from there?
     
  4. Oct 23, 2016 #3
    It's at the top right corner of the image, which has 0 x-coordinate, am i mistaken?
     
  5. Oct 23, 2016 #4

    haruspex

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    That's right. The vector along that diagonal is the difference between the endpoints, as vectors.
     
  6. Oct 23, 2016 #5
    However, I wrote zero in the i component in the answer space to part (b), does that mean the computer system is wrong and I am right?
     
  7. Oct 23, 2016 #6

    haruspex

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    No, zero is wrong. Write the vector expressions for the two endpoints of the diagonal and subtract the bottom left front one from the top right back one. No zeroes.
     
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