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Homework Help: Rotational Motion

  1. Apr 29, 2012 #1
    1. The problem statement, all variables and given/known data
    Attached 1st pic is the question, 2nd pic is the formula

    PS: im sorry if i have posted on the wrong section.

    3. The attempt at a solution
    My understanding for this question is for compound pulley, angular velocity is the same, linear velocity is different. For pulleys in contact, linear velocity is the same and angular velocity is different.

    Since in this case, A/B are compound pulleys whereas B/C are contact pulleys.
    But the question did not give me any acceleration info on any of the pulleys, so I don't know where to start..

    The only info that I can gather is:


    So I tried to use s=rδ formula.

    Although I managed to get "1" of the answer, but the info I used was all from pulley A but the answer they want is gears B/C so I'm abit confused here.
    Hope someone can help me out.


    Attached Files:

  2. jcsd
  3. Apr 29, 2012 #2


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    Science Advisor
    Homework Helper

    welcome to pf!

    hi freshbox! welcome to pf! :smile:
    start by finding the (linear) acceleration of the weight D :wink:
  4. May 1, 2012 #3
    Hi tiny-tim thanks for the tip, i solved the problem already :)
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