My students may be reading this, so I don't want to put a damper on their parade, but we're going to scale back that thing a lot
It's unsafe, too powerful, and too big. However, they were looking for proof that they could actually launch the ball far enough. We kept asking them "ok it looks cool on paper, but how fast does this need to go? how much torque? how big of a wheel?" until they decided to build a prototype and test it. This thing only took a few minutes to build and we only launched the ball twice. It's now decommissioned