What are the Equilibrium Conditions for a 3D Rigid Body with Applied Forces?

AI Thread Summary
The discussion focuses on determining the equilibrium conditions for a 3D rigid body subjected to multiple forces, specifically a rod assembly with a ball-and-socket joint and a journal bearing. Key calculations involve finding the reaction forces at points A, B, and C, with specific attention to the components along the x, y, and z axes. Participants emphasize the importance of using the correct equilibrium equations, particularly the sum of moments and forces equating to zero. One user expresses frustration after spending extensive time on the problem without success, highlighting the challenge of setting up the equations correctly. The discussion underscores the necessity of understanding the relationship between forces and moments in achieving equilibrium.
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Homework Statement



The rod assembly shown has a ball-and-socket joint at A and a smooth journal bearing at C. The forces F1=600N , F2=410N , F3=460N , and F4=950N are applied as shown in the figure. The geometry of the rod assembly is given as a=0.900m , b=0.650m , and c=0.800m. Neglect the weight of the rod. The journal bearing supports the rod in such a manner that it is free to rotate about the y axis.

1.)Determine the magnitude of the y component of the reaction at C

2.) Determine the magnitude of the z component of the reaction exerted on the rod at C.

3.) Determine the magnitude of the z component of the reaction on the rod at B.

4.) Determine the magnitude of the x component of the reaction on the rod at B.

5.) Determine the magnitude of the z component of the reaction on the rod at A

6.) Determine the magnitude of the x component of the reaction on the rod at A

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You have 6 unknown reaction forces and 6 equilibrium equations. Can you set those up?
 
When summing moments = 0, sum about axes, not points. Like
Sum of moments about z axis = sum of F_x(y) + F_y(x) , where y and x are the perpendicular distances from the line of action of F_x and F_y respectively, to the z axis. Etcetera for other axes with appropriate subscripts. 7 hours, those were the days my friend I'd thought they'd never end...
 
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