The ball should have "Dynamic" physics. That's so it can bounce against the wall elements, which are "Static" elements. (The walls shouldn't move.)
The bouncing actually comes from the "Bounce" JavaScript, which is run when a Mouse Down or Mouse Over event happens. It's an action that moves the ball upward, not physics. Is it confusing? Totally. That's why the "Is there a Physics API" thread is so long. The "Bounce" example is trying to get Hype to do something it doesn't excel at.
Matter.Body Module - Matter.js Physics Engine API Docs - matter-js 0.19.0 - If access to Matter.js was unrestricted, it's simply just a use of the Matter.Body.setAngularVelocity(body, velocity) API.
No changes of the current version of the book are planned. Adding video makes the project massive, so that's why it's a new project. So far, people unanimously want video...
So I figure I'd create new examples and then just do a video for each section, explaining what that section is about. I'm realizing that people don't like to read. Although, trying to learn from a video can also be annoying. So the idea is that both options are available. A video could very likely be a read-through of the section.
I haven't started that though. It's a huge project and I don't know what's up with Hype 4, so I'm working on a Hype scripting project right now.