Hit force between two objects

Hello. I am working on a car game. I would like to make some kind of destruction system. When car drives in to something, I would like to calculate what was the force of the impact, and apply damage accordingly. I calculated it by multiplying velocities of both objects, and multipling it by the mass, but it does not take hit normal into account, and I think that it is very important factor.

I discovered that “Normal impulse” works like a “force” of hit. Am I right? What would be the best way to calculate force of collision? Or maybe I dont need to calculate it, because “Normal Impulse” will work? Thanks in advance.