I am trying to understand how the concept of moment was introduced in physics. For example I don't understand how the formula of the moment of impulse was created. Specifically I don't understand why the multiplication with R (L=PXR, or torque=FXR). Is it demonstrated by experimentation, or the multiplication with R is just a "trick" so the formula is depenent on angular acceleration (in this case for torque ) or other rotational components ? I guess the best way to find out is by seeing the demonstration of the physcist who created the concept of moment but I can't find anything about it. Can somebody help me ?