Hello, i am on a robotics team and working on creating a robot to compete at www.usfirst.org competitons. im having a hard time constructing a formula that will find the ideal center of gravity for our robot arm attachment. here are some specs: length (at the base) 38 in , width 28 in (at the base), height 60 in (at rest, the arm needs to extend so that it can place a 3 foot tall tetrahedral on top of an 8 foot goal) so the arm is going to have to be aprox. 3 feet off the top of the robot. the tetra weighs 8 pounds. the weight of the robot is not determined yet, but the max weight it can be is 120 pounds. any kind of help to get me started would be great. thanks.