1. Not finding help here? Sign up for a free 30min tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Rotary (Gears) question - angular acc/velocity involved

  1. Sep 29, 2013 #1
    Rotary (Gears) question -- angular acc/velocity involved

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

    EyhIekI.png

    2. Relevant equations

    w (angular velocity) = alpha (angular acceleration) t
    w1 / w2 = r2 / r1
    |a| = sqrt( (a(tangential))^2 + (a(normal))^2 )


    3. The attempt at a solution

    Since A has a constant angular acceleration, w = alpha t

    For gears A, B: wA/wB = r2/r1
    For gears B, small B: wB = w(small B)
    For gears small B, C: wC = r1/r2 * ((r1*wA) / r2)
    Thus wC = ((r1)^2 * wA) / (r2)^2
    And thus wC = ((r1)^2 * alpha * t) / (r2)^2
    Subbing in values... wC = (150^2 * 14 * 0.8) / 250^2 = 4.032 rad/s

    Now

    wA = 0
    alpha A = 14

    and

    wC = 4.032
    alpha C = (r1 * alpha A) / r2 = 8.4


    So

    a(tangential) = alpha C * r2 = 2.1
    a(normal) = (wC)^2 * r2 = 4.064
    |a| = sqrt( 2.1^2 + 4.064^2) = 4.57

    However this is not correct...

    Could someone point out where I may have gone wrong?

    It would be greatly appreciated, thank you
     
  2. jcsd
  3. Sep 29, 2013 #2
    I ended up getting the right answer.

    alpha C = (r1 * alpha A) / r2 = 8.4
    shouldve been
    alpha C = (r1/r2)^2 * alpha A
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?
Draft saved Draft deleted



Similar Discussions: Rotary (Gears) question - angular acc/velocity involved
Loading...