A Public Service Announcement on Guns and Bullets

What I saw there, while interesting from a mildly voyeuristic point of view, disturbed me in two ways. The first, and obvious one, was that I was upset that this was happening in my country, again. The second was concern, because it was really evident from some of the footage, that my fellow Americans watch way too much television and thus have a false understanding about bullets. So this afternoon’s public service announcement is to try and prevent possible harm that might otherwise be avoided.

An excellent article, as far as I can tell, with one caveat:

Power, with guns, is dictated by physics. As my father the physicist taught me at way too early of an age, F = M x A. Force = Mass x Acceleration. The striking, or penetrating, power of the bullet is determined by how heavy (mass) it is, multiplied by how fast it is moving. Thus, a small bullet, moving at extreme speeds, can cause a lot of damage. A large bullet can move at much slower speeds, and cause the same damage. All other things being equal, however, the higher the speed, the greater the penetration. Now, that word “penetration” is one you should think about.

He’s not describing F = ma here. Mass*velocity gives the momentum, but one also needs to look at the kinetic energy. A small bullet moving at some speed has the same momentum as a bullet of twice the mass, moving at half the speed, but it also has twice the energy, and that has some effect on penetration. The salient point, I believe, is that you don’t want that energy deposited in your body, and that’s true regardless of which case you have.