Re: [Phys-l] Final velocity of bullets

[Stefan Jeglinski <jeglin@4pi.com>]

> It is true. I live in Hermosillo, Sonora, México and I read in the
> newspaper, a few years ago, about someone who kill himself by shooting his
> gun in a vertical direction. The bullet of his own gun hit his head.

Now _this_ seems exceedingly unlikely to be true. 
Even if one assumes "perfect" conditions with 
respect to wind, recoil during fire, etc, one can 
use the range equation to determine that this gun 
would have had to been fired within a hair of 
perfect vertical. Actually, less than a hair, 
based on the standard range equation: sin(2theta) 
= Rg/V0^^2

Even assuming that the cross section of the head 
is based on a 1 meter radius (the range), a very 
generous assumption, and a muzzle velocity of 
300m/s, we get something close to 2theta < 1E-4, 
where theta is the traditional trajectory angle 
in range problems. Over the length of the barrel 
of a pistol (15cm?) this angle subtends a 
distance from the barrel centerline of about 
10-20 micrometers (ballpark). A strand of hair is 
on the order of 50-100 micrometers thick.

It would take an exceedingly unlikely combination 
of conditions to make this newspaper account 
possible. Is there any confirmation?


Stefan Jeglinski