# ME Practice Problem (Lindeburg) 43.6



## jsnelson (Jan 29, 2013)

I'm wondering if someone could give me a bit of a sanity check on this problem (if I'm posting this in the wrong area...my apology). This is a static problem in the Lindeburg Practice Problem book Chapter 43 Problem 6. The statement says that "Points A, B, and C are in the same vertical plane". I worked on this for quite some time last night and when I turned to the solution I was pretty shocked how they handled it. The solution doesn't really give me the impression that all three points are in the same vertical plane by how they consider the free-body diagrams.

Would someone mind giving me a sanity check or a different way to view this problem. I feel like I'm missing something in the problem statement that would clear up how to proceed or that might indicate what is going on in the solution. I actually thought that this might be a incorrect and looked it up on the ppi2pass errata page and didn't find it listed.

What has me wondering is that they have a freebody diagram in the x-y plane that shows an x component of the reaction at C and another in the x-z plane showing the reaction of the x component of the reaction at B. If these points were all in the same vertical plane why does the FBD not show the other reactions and why only a reaction to C in one FBD and a reaction to B in the other.

At this point I'm pretty convinced that it is the way I'm looking at the problem so any help with this problem would be appreciated.


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## CRNewsom (Jan 30, 2013)

I no longer have the problem/solution manual. If you could scan your interpretation of the problem, I would be able to take a look at it. I do not recommend scanning the actual book page.


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## ongreystreet (Jan 30, 2013)

Which breadth are you studying for?


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## jsnelson (Jan 31, 2013)

Sorry for the delayed response, it's been a bit hectic at the office. I'm studying for mechanical systems exam. I'll get something posted soon on my solution and how it compares to the posted solution.


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## SNAPE/SMOTT PE (Feb 10, 2013)

After reviewing this problem, from my understanding you are supposed to look at the dashed line from A to C as representing the z plane, and the dashed line from A to B as representing the y plane. So when looking at the free body of the xy plane, point C is the only one that "ventures out" of the xy plane. Since the problem states that at point A all angles are 90, point C will have a y coordinate of 0 and an x coordinate of some number when looking at the xy plane. So that is why there is a Cx in the free body.

Does this make sense, it's hard for me to explain.


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