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 problem - Kinematics of Rigid Bodies

  1. Nov 14, 2008 #1
    1. The problem statement, all variables and given/known data
    There is a slider-crank mechanism. Express the angular velocity omegaAB and angular acceleration alphaAB of the connecting rod AB in terms of the crank angle theta for a given constant crank speed omega naught. Take omegaAB and alphaAB to be positive counterclockwise.

    The structure is a point A free to slide laterally connected by a rigid rod of length l to point B. Point B is connected to another point O by a rod of length r. The crank angle theta between r and the horizontal is given, as is the crank speed omega naught. Take omegaAB and alphaAB to be positive counterclockwise.

    2. Relevant equations
    velocity = r * omega
    acceleration tangential = alpha * radius

    3. The attempt at a solution

    I first tried to define the horizontal distance between A and O. I found x to be r*cos(theta) + sqrt(l^2 - r^2*sin(theta)^2)
    At this point I took the derivative of x to be the velocity, and I divided the velocity by x.

    At this point I have an ungodly mess and I have no idea how to put omeganaught into the equation. I feel like I just need to understand the relationship between x or theta and omega naught to understand the equation, but I do not. I apologize for the lack of a graphical representation of the problem.
  2. jcsd
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook

Can you offer guidance or do you also need help?
Draft saved Draft deleted