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Homework Help: Me(a vector problem)

  1. Jan 22, 2009 #1
    plz help me(a vector problem)

    1. The problem statement, all variables and given/known data

    i m very confuse about this assignment. plz help me how to prove.

    If [tex]\vec{}A[/tex] has constant magnitude show that [tex]\vec{}A[/tex] and d[tex]\vec{}A[/tex]/dt are perpendicular provided that d[tex]\vec{}A[/tex]/dt [tex]\neq[/tex]0

    also give one physical example of this problem.

    plz help me in this problem.


    2. Relevant equations

    3. The attempt at a solution
  2. jcsd
  3. Jan 22, 2009 #2
    Re: plz help me(a vector problem)

    This can be thought of as a circular motion problem with constant radius. Since the radius vector has a constant magnitude (constant radius), then only the position of the vector changes with time. Draw two vectors with magnitue A, one displaced an amount delta theta from the other. Find the vector difference which will be delta A, then take the limit of delta A divided by delta theta as delta theta goes to zero.
  4. Jan 22, 2009 #3
    Re: plz help me(a vector problem)

    i didnt got u !!!

    Hey Chris buddy can u plzz solve it for me plzz..

    thnx in advance.
  5. Jan 22, 2009 #4


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    Staff: Mentor

    Re: plz help me(a vector problem)

    No, we will not solve this for you. You have been given a great hint, and now the rest is up to you.

    Please re-read the Rules link at the top of the page, especially the part about how you must do the bulk of the work on homework/coursework problems.

    Show your work, and if you have a specific question, we can offer hints and tutorial help. We do not do your homework for you.
  6. Jan 22, 2009 #5
    Re: plz help me(a vector problem)

    ooops sorry !!

    I didnt knew the rules..
    it wont happen next tym.
  7. Jan 22, 2009 #6


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    Science Advisor
    Homework Helper

    Re: plz help me(a vector problem)

    The magnitude of A squared is A.A (dot product). Is that a help?
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