Re: [Phys-l] Final velocity of bullets

[Brian Whatcott <betwys1@sbcglobal.net>]

At 08:35 AM 1/24/2007, Michael, you wrote:

> ///    I think we are agreed that a bullet fired
> straight up will land at terminal velocity.  I think we are also agreed
> that a bullet fired at steep angle, but not straight up, will land with
> some horizontal velocity in addition to terminal vertical velocity.  Is
> there an angle of launch above which a typical bullet is not lethal.
> (And I think we realize this is gun and bullet dependent.)
> ///
> Michael D. Edmiston, Ph.D


Preamble: I see I am in imminent risk of becoming that
 bane of lists - the contributor who takes ownership
 (in his mind) of a thread: so I will attempt to be brief.

I don't agree with Michael's paragraph above and I suspect it
illustrates a difficulty that Rick also hinted at with his model.
Here are the fatal words:
" [it] will land with   some horizontal velocity in addition to
 terminal vertical velocity".

While it is  insightful to point out the separation of horizontal
and vertical motion for assigning gravity mediated
acceleration,    it is an error to suppose that terminal velocity
 is something that affects only the vertical component of velocity.

Air drag in fact opposes the instantaneous direction of flight as a
generalization   I therefore hope that the sentiment was just a locution
rather than a carried over concept.


Brian Whatcott    Altus OK    Eureka!