[Venkatesh]

Oh the wonderous answers I have unleashed,

I started playing the idea of center of percussion today, rather sleep though a physics movie =). I took a pen and hung it on a paper clip. Then I hung this paper clip-pen compound on a pencil. I marked the spot at which the paper clip started and then provided it with a force at varying spots. At any point beyond 2/3rds of the length of the pen, a force causes a forward motion of the paper clip. At any point between the center of mass of the pen (determined experimentally), an applied force would cause the paper clip to slide backwards. Very cool, since it goes against intuition and first guesses.

I guess I need to reconsider the initial problem. It was just a thought experiment, since I was bored of watching a friend play on the GBA SP. The idea was born because I was thinking about rotational collisions and conservation of angular momentum in such systems.