Completely aside from the point you're trying to make: it's a pet peeve of mine when people try to describe collisions in terms of kinetic energy. It's the wron

Completely aside from the point you're trying to make: it's a pet peeve of mine when people try to describe collisions in terms of kinetic energy. It's the wrong metric--the important conserved quantity in collisions is momentum, which is simply linear mass*velocity (not quadratic velocity). After that, it becomes a matter of calculating the rate of momentum transfer, or impulse. That's why crumple zones are important for vehicle-vehicle collisions--not because they turn kinetic energy into a stored form of potential energy in deformation, but because they drastically decrease the rate at which momentum changes.