Circle-Arc Collision

As I develop my game GravSlide, I'm testing out and integrating various types of track pieces, to eventually have a full level editor. While I began with circle-rectangle collisions, which I now have functioning properly and performantly, the second type of collision that I would need is circle-arc collisions. This collision seemed mathematically daunting at first, as a vector pointed into the concave of an arc must be reflected against the normal of its initial angle of entry (wordy, right?). However, as you can see from this isolated example (and testing grounds), circle-arc collisions now work as well.