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Homework Help: For the following three vectors, what is 3C·(2A x B )?

  1. Sep 16, 2007 #1
    For the following three vectors, what is 3C·(2A x B )?

    A = 2.00i + 3.00j - 9.00k
    B = -3.00i + 3.00j + 2.00k
    C = 5.00i - 8.00j


    2AxB=(12+54)+(8-54)+(12-18)

    2AxB=66i - 46j -6k

    3C·(2AxB)= (66x15)i + (-46x-24)j = 2094

    the app is telling me it's incorrect. I don't know what I'm doing wrong! thx in adv
     
  2. jcsd
  3. Sep 16, 2007 #2

    cristo

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    Check your k component of 2AxB
     
  4. Sep 16, 2007 #3
    looks like i was in the write spot sorry. checking...
     
  5. Sep 16, 2007 #4
    isn't k irrelavtant considering Cz is zero
     
  6. Sep 16, 2007 #5
    correction "right spot". I've been workin on this asssignment all day. I'm losing my attention to detail. Probably why I'm having trouble. lol
     
  7. Sep 16, 2007 #6

    dynamicsolo

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    Check this thread: https://www.physicsforums.com/showthread.php?t=185106 [Broken]

    and please do not multiply-post a problem in the future!
     
    Last edited by a moderator: May 3, 2017
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