One thing we are dealing with, which many of the physics equations ignores,The exaggeration response is a very real phenomenon. I've known my father-in-law for over 40 years, and he has always responded in a very exaggerated way to any physical contact, loud noises, or input. Damnedest thing I have seen. I quite sure he would be knocked down by a .22 lr round fired into a vest.
is we are shooting a live organism. Hit a nerve, or a contracted muscle mass,
or large hard bone, or a combination of the three, and there may be a flinch,
or movement, not necessarily backwards, from nerve response to the projectile impact.
Shot a Bobcat recently, at close range. It did a backflip, then ran ran off. Found it dead, some time later. How much of the flip was a reaction to the noise of the shot ? How much of the somersault was a reaction to being hit? Who knows, but obviously it was mortally
wounded, yet the impact of the round didn't push the animal over, or move it backwards
one bit.