We define torque as a quantity that tends to cause rotational acceleration in an object and that: [tex] \tau = F \cdot d [/tex] where d is the distance from the center of rotation. My question is, why was it defined in this way in the first place? It works, yes, but how did we know it'd work? Is it because toque is directly proportional to both d and f and the proportionality constant was experimentally proven to be 1? I was thinking there was more to it. Can someone please elaborate on this for me?