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Mar 23, 2008

Homework 6.75


So, attempting to solve this problem (6.75 is giving me problems).

I have drawn the FBD's and have done the Newton-Euler equations.

I have the only force in the X-Direction is the for P times the cos(theta) is equal to mass times the acceleration of the center of mass in the X.

I then have the only force in the Y-Direction is the force P times the sin(theta) is equat to mass times the acceleration of the center of mass in the Y.

I then have the moments summation equals (2)(sin(theta))(.1) equals I*alpha. [too some math liberties with the theta==45 degrees]

This is where I get stuck. I find the accel of the Center of mass for both X and Y. I then try and use them in a kinematic equation that relates the movement of the center of mass with point A[Ag = Aa + (alpha) x (R g/a) - (omega)^2 * R g/a ].

I used that the value of I = (1/12) m (a^2 + b^2).

My answer wasn't even close.



Can anyone help me and point out where my logic flaw is?


Thanks,

~Joel

1 comment:

CMK said...

Your process looks good. The equation for I_G is also correct. I do not see any problems with your process.

One detail. The moment about G due to P is: (2)*P*sin(45)*0.1. In your post, you left of the "P". Did you leave that off in your analysis, or is that a typo in the post?

The only other suggestion is to recheck your algebra and numerical calculations.