# Homework Help: Planar Kinematics

1. Oct 11, 2009

### aolse9

1. The problem statement, all variables and given/known data
The link AB has an angular velocity of 7.6 rad/s in the direction shown.

http://hdimage.org/images/mg122xouxwua5jzgn110.jpg [Broken]
Determine the angular velocity of plate BCD if the angles are as shown and AB = 58mm and BD = 111mm.

2. Relevant equations
VB = VA + VB/A

VD = VE + VD/E

VB/D = VB - VD
3. The attempt at a solution
I have made one long thought out attempt at this problem. Basically, I used the above equations, canceling out the velocity of the fixed points. Then by converting the velocities, to i and j components, I got two equations with 3 unknowns, 1. the angular velocity of BCD, 2. the angular velocity of BD and 3. the length BD. By simply counting the angular velocity of BD and the length BD as one unknown, I have 2 unknowns and two equations. My answer was 1.641 rad/s [clockwise]. But this answer is incorrect, any help would be greatly appreciated.

Last edited by a moderator: May 4, 2017
2. Oct 11, 2009