FHitResult normals for Sphere vs Triangle

Hello! It’s an noob question but still i can’t really figure out, which normal is responsible for what. i made some basic drawing to illustrate possible vectors on collision image?

(they are not correct, but that doesn’t matter) i just need to get the idea.
So which one is

a) Normal

b) ImpactNormal

or one of these is not present on the image? i would appreciate if someone could explain/illustate the correct normals then. (sphere/tri scenario, in case of vertex/edge collision it may refer as “Plane Normal” aswell)

or as i think about it right now… it’s always the same normal in both cases? still asking for clarification.

I’d like to have some clarification as well. The naming convention is confusing !

There’s also normal impulse, not sure what that is either.