Visualize a simple balance, a pan at either end of a beam which balances on a fulcrum. The way it works is that if each pan carries the same weight, it balances horizontally. If one pan carries slightly more weight, it tips slightly off horizontal. If one pan carries more weight yet, it tips farther off horizontal. But that is not the way it would work if simple physics is applied to my simple model: for equal weights it would balance horizontal or not, and for unequal weights it would rotate fully until it came to a stop, regardless of how unequal they were. There must be some simple explanation, but I have not been able to find it.