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Homework Help: Instantaneous Center

  1. Jun 18, 2016 #1
    1. The problem statement, all variables and given/known data
    Determine the angular velocity of the gear at the instant shown. Set v = 9ft/s and vc = 6ft/s. Assume counterclockwise is positive.
    2. Relevant equations
    v = w x rIC

    3. The attempt at a solution
    I tried solving this many times using va = v0 + (ω x ra0 ) and vb=v0 + (ω x rb0 ) but kept getting the wrong answer.
    Then I ended up solving for the instantaneous center using similar triangles and used v = ωxrIC.

    How do I know when to use an instantaneous center in my problem solving?
  2. jcsd
  3. Jun 18, 2016 #2


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    2017 Award

    Staff: Mentor

    Then the problem is somewhere in the steps you did not show.
    Just a guess: Did you take the signs into account properly?
  4. Jun 19, 2016 #3
    Instantaneous centre method can be used in any problem.
    But both methods give the same result. Maybe there's some problem with the signs like mfb said.
  5. Jun 19, 2016 #4
    Thank you for helping! Sorry there was such a delay in my response. Yes it ended up being just a calculation error when mixing up the signs!
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