I don't have the full version, so I don't think I can see the stuff behind your links. Haven't seen the catapult.
Did get past 13 too... Made a little car that got launched at high speed off a big tredmill contraption, and got there before the ball fell. Barely. After much tweaking.
Then watched other's solutions, and saw that you could just roll the ball out of the way. Well, sure, if you want to go the simple way...