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Homework Help: Circular Motion probem 2

  1. Sep 4, 2013 #1
    Hi friend the problem is as follows:




    Please friends help me in this.
    Thank you all in advance
    Last edited by a moderator: May 6, 2017
  2. jcsd
  3. Sep 4, 2013 #2
    Instead of using a=dv/dt use a=vdv/ds.

    The given condition is |aT|=|aN|

    i.e -vdv/ds=v2/R .

    Integrate with proper limits and you will get the answer.
  4. Sep 4, 2013 #3
    Thank you very much tanya. I got the answer.

    But Was I doing it in wrong manner?
  5. Sep 4, 2013 #4
    You got the answer with your approach or the one i asked you to do ?
  6. Sep 4, 2013 #5
    By your approach.
  7. Sep 4, 2013 #6
  8. Sep 4, 2013 #7


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    Homework Helper

    The particle was decelerating, so your first equation should have been a=-v2/R. The other error was, that when you integrated v with respect time, you forgot the lower limit of integration. So your result is dimensionally incorrect. Tanya's solution is very elegant and simple, but yours is also all right if you do it properly. :smile:

  9. Sep 4, 2013 #8
    The lower limit of time should be zero. The question states that.
  10. Sep 4, 2013 #9


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    Homework Helper

    Yes, but you have ln(R-vot), it is not zero at t=0.
  11. Sep 4, 2013 #10
    After integration when you put t=0,the term doesn't vanish.You have erroneously assumed it to be 0.
  12. Sep 4, 2013 #11
    Thank you very much friends. I got the answer. Problem has been cleared.
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