you're not good at it.
and Luis Alverez agrees with me.
Ophiucus shows a lot better grasp of basic physics than do you, Oztrich.
The bullet imparts some of its momentum to the mass of the head... in the same vector the bullet it travelling. The bullet also imparts some of its momentum to parts of the brain, some at different vectors, all of which will be between 0 and <90 degrees from the vector of the invading bullet. Many of these brain parts will strike other brain parts, imparting part of their momentum to the struck parts, overcoming their inate inertia, further attenuating the energy transfered to these parts... which will, in turn strike other parts, and so on until the entire energy is shared by all parts in some way or another. This process can be described as a wave of force moving through the material. If the bullet stops in the skull, it has successfully transfered ALL of its momentum to the head.
By your logic, the bullet, after passing through the head, would have the same tendency to propell the head backwards by the opposite and equal reaction... that doesn't happen... nor does it happen with the material to which it has imparted energy.
If Luis Alvarez agrees with you, please have him post the math that proves the "rocket powered by brain mass" theory.
I have to admit - I had to look up Luis Alverez (or Alvarez). Found an article on iridium finds and the theory that a comet or large meteor collision caused the death of dinosaurs and a couple on his involvement in UFO hoaxes - debunking I'm sure. Then I found this gem on Jet Effect Theory
It discusses Alverez's Jet Effect Theory and its publication and analyzes the experiment. Some highlights:
Of course, I'm not a recognized physicist. I only took a couple years of physics as an undergrad, covered the kinematics of trauma and gunshots for medic training, studied anatomy, physiology, trauma forensics in grad school and med school. So I'm not playing physicist - I'm looking at a trauma situation and an explanation that doesn't match with my training and education.