How can I find the angle θ for mechanical equilibrium in this problem?

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Homework Help Overview

The problem involves finding the angle θ for mechanical equilibrium in a scenario with forces acting on a rod, including normal forces and weight. The context suggests a focus on moments and force summation in a frictionless environment.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • The original poster attempts to clarify the forces involved in the problem, specifically asking about the summation of forces in the x and z directions and the location for taking moments. There is also confusion regarding how to express the angle θ in terms of other variables like M, W, and I.

Discussion Status

The discussion is ongoing, with participants expressing frustration and confusion about the problem. Some guidance has been offered regarding the summation of forces and moments, but there is no clear consensus or resolution yet.

Contextual Notes

Participants note that this problem is commonly challenging for the class, indicating a shared struggle with the concepts involved.

caddyguy109
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This problem was part of a post in another thread, but it got really messy over there and no one seems to be responding.

So, here's the problem:
http://www.ihostphotos.com/show.php?id=182816"

And I was told this (but it didn't really help me see what to do, much):
"at least it's a 90 degree angle! and frictionless ...
try taking Moments around the place where the two F_N intersect
did you sum F_x and F_z first?"

But what forces do I sum for Fx and Fz? And where exactly is that total moment taken about?

On the FBD, I drew the W force pointing straight downward from the center, as specified, then Na (Normal Force A) perpendicular to the slope on the left, and did the same, but as Nb, on the right. This part makes sense, theoretically, to me at least.

But what the HECK do I add/calculate/find, etc. to get "the angle θ corresponding to equilibrium as a function of M, W, and I"? Still don't know what exactly to do or where to start, as far as finding that.:frown:
 
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Anyone??
 
This problem is REALLY driving me nuts...:mad:
 
:rolleyes: ...this problem really must be confusing. Seems to be the one all of us in the class are getting stuck on right now.
 
The moment is a free vector, unlike the forces that are sliding vectors, you have two normal forces acting on each of the ends of the rod. The advice given to you is a good one, but try checking sum of Fx, you might get suprised.
 
Okay, THINK I got it.
 
Last edited:

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