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Something about applied dynamics.

  1. Feb 18, 2010 #1
    http://img211.imageshack.us/img211/6048/a1a1.gif [Broken]
    http://img17.imageshack.us/img17/6684/b1b1.gif [Broken]

    May i know actually why initially 2SA+SB=l , but after differentiate, it becomes 2 aA = -aB ?
    why does the l disappear?
     
    Last edited by a moderator: May 4, 2017
  2. jcsd
  3. Feb 18, 2010 #2
    This thread does not belong here. Please move it to the homework thread.

    Matt
     
  4. Feb 18, 2010 #3

    tiny-tim

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    Hi aiklone1314! :smile:
    2SA+SB = l, so 2aA+aB=0 (because l is a constant), so 2aA = -aB :wink:
     
  5. Feb 18, 2010 #4
    but how to know SA and SB is not a constant?
     
  6. Feb 18, 2010 #5

    tiny-tim

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    If sA is constant, then vA and aA will be 0 (same for sB)
     
  7. Feb 18, 2010 #6
    ok thank you very much...
     
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