I have an interesting problem. I am involved in a historical fencing group which uses blunted swords to thrust with (think fencing foils and épées, but heavier and stiffer, with a rubber blunt on the end). We've been discussing various new weapons and needed to address safety. I decided to gather some actual data. I mounted a Force Sensitive Resistor on the tip and am polling the resistance with an Arduino. At about 25kHz, I am getting really nice curves showing force over time (a sample can be seen here: http://lh4.googleusercontent.com/-N.../AAAAAAAAIms/bVAbGUvkxlM/s2048-no/IMAGE_1.jpg ). The problem is how to interpret the data. I was hoping to figure out total energy transfer, but I now realize that the area under the curve is impulse, not energy. The collision is highly Inelastic - the sword bends, the target is squishy, etc. I really have no way to measure displacemen, and the energy transfer is far more than just the distance things move - there's mechanical deformation, possibly chemical changes in the target's body, etc. Is there any way to get the energy of the impact? If not, what does the impulse actually mean in this case? I'm used to thinking of it as change in momentum in a classic elastic collision setting, less sure of what it means here. The ultimate goal is to figure out how "hard" an impact is. The concern is a) injury and b) penetration of the (cloth) armor worn. Any thoughts on the best way to quantify this from the data? Should I just look at peak force and ignore the "width" of the peak? Any advice would be appreciated.