The Physics of Terrifying Technological Battlebot Tactics

It is essentially a modern technology-based sporting event in which teams build remote controlled robot-like things that fight in an arena. Two robots enter, one robot leaves--and on May 11, the eighth season of the showdown begins. Of course, there are many engineering aspects of these bots--but underlying every bit of technological terror is some very fundamental physics. Let's go over some of the physics-based tactics used in the game. How many of the robots have spinning-based weapons? It seems to be a popular choice.