I am new to the forum and to the First robotics competition so I will give this my best shot. My team, 624, was wondering the same thing about the weight of the big yellow ball. However we decided that the wait wasn't a problem, with the weight being only a couple of pounds. The real problem we decided was the inertia the ball will have if you are lifting the ball off the four foot goal and then trying to move with it. That could be a real problem, possibly rocking the robot badly or even tipping it over. So we have not really come up with a solution to this, we kinda just went around it and have been trying to get the more basic design of the robot done first, like the components we want as well as our drive train.