our arm looks similar to yours so i'm curious to see how well it throws. We have 3 joints(base, elbow, and the grabber at the end is on a short joint) If you roll that all up with a box and then open it as the arm swings over the top of the robot we can get a cool trebuchet like effect. Now all it has to do is be finished... maybe tomorrow. I'll tell you if it works ^_^
With a 9 foot arm like ours it doesn't have to be moving fast to make it over the ramp. Its already sooo high up... Eat that tower of Babel!
Anyway the arm theoretically does 90 degrees in 1.2 seconds and that means the end is moving about 15 feet per second. but those calculations are very optimistic. Earlier in the competition i calculated that the box would have to be going 20 feet per second or something close to that to get about 30-40 feet of distance which is about 80 foot pounds i believe. But that was calculated from the ground. I guess if you combine that movement with that of our second joint the box would be moving at approximatly 20 feet per second. So maybe just maybe it will work.
P.S. i don't think our ceilings are high enough to test this....