Hello all, Since I have run into the problem of regularly leaving moments out of my free body diagrams (and vice versa), I thought I'd pose a question on the topic. In trying to wrap my head around the concept, I've gone back to the beginning of the semester's notes and that didn't really help, nor did the tutor I asked. I guess I never fully grasped moments must have managed to coast by because of my superficial understanding . But now that we've started covering internal forces, I see that I need to understand it better. So my question is, how do you look at something at tell whether or not there is a moment acting on it? Are there any specific cues? I don't know, I guess I need a checklist or something. I've found something like that to identify zero-force members, and even something similar to help with analyzing friction problems. But it would appear that moments are assumed to be... self explanitory or something. In order to have something more specific to wok with, I've drawn up a one of the things I've struggled with recently - that's the file attached. So, say you have a frame like that, with pin connections at the base (By the way, for anyone with a Hibbeler 10th edition on hand, it's the diagram for Prob. 7-34). If the member AC were removed (making CB a cantilever), there wouldn't be a moment about that point. A tutor told me that but didn't do a good job of explaining why. I thought a downward force applied at the end of a cantilevered beam would always produce a moment, because it's only supported at one end. Or is it to do with the type of connection. Or maybe because I'd disassembled the frame and that changed something about the interactions... I'm confused. :uhh: I'd appreciate any input at all. Thanks. M.