Physics Help Forum find angular velocity of system PLEASE!

 Periodic and Circular Motion Periodic and Circular Motion Physics Help Forum

 Aug 18th 2011, 04:37 AM #1 Junior Member   Join Date: Feb 2010 Posts: 6 find angular velocity of system PLEASE! 1. The problem statement, all variables and given/known data angular acceleration of line a= -2w^2 rad/s when theta=pi/6, w= 10 rad/s what is angular velocity when theta= pi/3? 2. Relevant equations chain rule 3. The attempt at a solution w= e^-2theta is my answer, but I know this is wrong I know that this question is really easy, but I just don't know how to get it
 Sep 21st 2011, 03:02 PM #2 Physics Team     Join Date: Jun 2010 Location: Morristown, NJ USA Posts: 2,337 Start with a= dw/dt and apply the chain rule: a= dw/d(theta) x d(theta)/dt. From this you can derive 2 a theta = w^2 + C, where C = an unknown constant Substitute for a: 2 (-2 w^2)theta = w^2 + C Rearrange: w^2(1+ 4 theta) + C = 0 Given that w = 10 when theta = pi/6 lets you find the value for C. Then solve for w when theta = pi/3.

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