There is a lot of confusion on where the weight of the sign acts. Is the sign and bar separate rigid bodies (I.e. weight acts at 6L) or are they separate bodies (ie weight acts at 5L)?
Because the sign is rigid and the beam is not, would we assume that there is a reaction moment acting at the attachment point b/w the sign and the beam that we also have to account for?
Yes, you should first do an FBD of the sign with its weight and reaction force and moment to find those reactions; then an FBD of the beam with reactions at A and the end of the bar to find rxns at A.
You can do this as Lukas described, or you can also do equilibrium of the beam-sign system (with the weight force acting 6L away from the fixed end) to find the reactions at A. Both methods should result in the same answer.
Are we supposed to say that the sign generates a moment at the end of the bar due to there being a horizontal distance "L" between the center of mass of the sign and its connection to the bar?
I think so. In the end, I believe you might have a force and a moment (both due to the sign) in the end of the beam
Do we solve this in terms of w? Since I is in terms of w and w is not given.
Nevermind I see we are finding w
For part (b), what value do we assume to take as w?
I don't know definitively, but the answer from part (a) makes the most sense.
Hey, are we supposed to say that the sign generates a moment at the end of the bar due to there being a horizontal distance "L" between the COM of the sign and its connection to the bar?
I believe so. You can either treat the beam as 5L long with a moment at the end, or 6L long and analyze it at 5L.
I just want to appreciate the LOTR reference.
I am able to find equations for slope and deflection using the second order method, but I am unsure how to relate this to finding w. Does it have to do with the second area moment for the beam?
I believe so, EI should be in your equation for v and w would be in your equation for second moment area. So you can get w from those relations
Is there an example from the book or on the website that is similar to this?
Are the dimensions of the sign, used at all for this question?
I only used the fact that the point where the mg force occurs is L meters away from the 5L beam in the x direction.
Should we consider the moment that the sign generates at the attached point or from the center of mass of the mass of the sign which x = 6L?
I believe focusing on the moment that the weight of the sign generates at the attached point on the beam is the correct approach.
Will the moment found from the FBD of the sign have the opposite sign when viewed on the beam?
The moment would act in a CW direction with respect to the wall, as the weight of the sign is a downward force.
How should I deal with the part that the sign exceed the beam. Should I add a moment at the connection?
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