Maybe the upside-down question mark confused people. I thought this thread would get a response. It's not like @jonathan to ignore people – especially not posters like Hans, who have been very active on this website.
But if the length of this thread is a guide... https://forums.tumult.com/t/is-there-a-physics-api/2183/ ...my expectations are low. It was started over two years ago, has over 100 responses, and yet I still can't do basic things like collision detection, change/set velocity or add/remove bodies.
Basically, it's the stuff here... http://brm.io/matter-js/docs/ ...there is humongous potential here. Ah, but it's like "Waiting For Godot".
Godot was chosen due to its relation to Samuel Beckett's play Waiting for Godot, as it represents the never-ending wish of adding new features in the engine, which would get it closer to an exhaustive product, but never will.
For me, this is especially frustrating, as first I waited for GameSalad to get better. Then, I waited for Stencyl to get better. Now, I'm waiting for Hype to get proper Physics. I waited so long that I seem to have lost interest in making video games. Maybe Hype 4 will rekindle that enthusiasm. But so far, I have a lot of unfinished games sitting on my hard drive.