hallo all, I was wondering if you were able to help me with the following: I am wondering about how body armor works exactly and have checked some sites, but still strugle with some questions. As for know I have the following: when a bullet hits a body, then you have injuries caused by the bullet itself (a hole in your body) but there is also the impact of the bullet on your body: the bullet has a certain amount of kinetic energy and this energy is given to your body. Now first question: a bullet hitting the body is this an elastic or inelastic collision ? I was thinking that when the bullet leaves the body its inelastic and when the bullet stays in the body its elastic. Now the body absorbs some energy, but how can I state this? I was thinking that the impact of the bullet causes the bullet to "give" his kinetic energy to the body by causing waves to occure, these waves, wich are actually Oscillations , causes injuries in the body as the body can only take a certain amount of oscillations, energy. I wonder how I can explain the wave and Oscillation story better. then I wonder about the following thing: a body armor will try to spread the energy of the bullet , so that the body can cope with the energy (waves) but what if you fire 2 times very fast ? Does interference occur then? I mean: positive interference because you have 2 waves very shorty after each other, meaning they will be added up and thus you have a wave that is a lot bigger? or? thanks in advance.