1. Limited time only! Sign up for a free 30min personal 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!

Homework Help: Dynamics: Angular Acceleration of Rods Connected to Disk

  1. Jul 9, 2011 #1
    1. The problem statement, all variables and given/known data
    Bars BC and AB and dish OA are attached by a pin like in the picture. The dish has a constant angular velocity [itex]\omega\_{0}[/itex]. Find the angular acceleration of bars BC and AB.

    2. Relevant equations
    Relative Motion Equations:

    3. The attempt at a solution
    So far, I have this written down:



    Still just fumbling over these equations. Any help is appreciated.

    Attached Files:

    Last edited: Jul 9, 2011
  2. jcsd
  3. Jul 10, 2011 #2


    User Avatar
    Science Advisor
    Homework Helper

    welcome to pf!

    hi vercingortix! welcome to pf! :smile:

    (have a theta: θ and an omega: ω :wink:)

    (centripetal acceleration is irrelevant)

    ω = (vP - vQ)/PQ

    so find vB as a function of θ :wink:
  4. Jul 10, 2011 #3
    That equation looks foreign to me. What I'm currently trying to do is solve for angular acceleration of the bar by knowing the omega and accelerations of both A & B. Something like the second equation in my original post. I'm very lost.
  5. Jul 11, 2011 #4


    User Avatar
    Science Advisor
    Homework Helper

    hi vercingortix! :wink:

    ω = |vP - vQ]/PQ


    α = |aP - aQ|/PQ

    are the definitions of angular speed and acceleration

    so find the x,y components of B as a function of θ, and differentiate to get vB and aB :smile:
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook