I'm tossing around an idea in my head, but I'm outside of my knowledge base. A guitar string is suspended between two points (nut and a bridge) and tightened to a certain tension. I assume most of the stress is in line with the strings, but force can do funny, counterintuitive things. I want to find how much downward pressure, perpendicular to the strings, is acting on the bridge. Or how much upward pressure the bridge is exerting against the strings. Or whatever. I don't have test equipment, I'm hoping for some math and principles so I can figure out a realistic range of real world possibilities. What variables and formulas do I need? Website/book recommendations are awesome. I can RTFM. I just don't know where to begin.