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Homework Help: Free body diagrams convention

  1. Jun 19, 2013 #1
    Do you normally write the magnitude of the vectors in free body diagrams? I have homework on this. Is there any convention when writing the magnitude?
  2. jcsd
  3. Jun 19, 2013 #2


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    It's not clear what you mean by 'write the magnitude' of a vector. Can you give some examples?
  4. Jun 19, 2013 #3


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    I'm not sure what you are asking. Sure you write the magnitude (in newtons or whatever) if you know it. Otherwise, write it as a variable and try to solve for it later.
  5. Jun 20, 2013 #4
    Magnitude as in the "length" or norm of the vector i.e. 5N, or 4m/s.
    So, there's no convention that forces you to write the magnitude if you know it at the beginning of a problem?
  6. Jun 20, 2013 #5
    One is usually better off using symbols for known and unknown quantities alike, and using algebra to express unknowns via knowns. The numbers can be plugged in at the very end.
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