Deadly Force

[RPM]

[offtopic]

Re: terminal velocity of a bullet if free-falling

I seriously doubt it would reach 400 fps. Air resistance etc. is a considerable factor on a small body. It might reach that speed in a vacuum ...

You don't hear about dozens of women and children being killed when you have a heavy hailstorm ... quite a few of those hailstones are of that size.

Also, having committed multiple sins as a kid with my air-rifle, I can attest that 300fps will take out a crow (air pistol). 500fps was the minimum for a squirrel (friend's air-rifle). I have seen groundhogs survive a .22 short to the vitals (around 850fps).

I have to think that it would be a fluke if a person was unfortunate enough to die after being hit by a 400fps projectile. Maybe in through the eye-socket or some other such unlucky spot.

Not exactly scientific - but there ya go!

P.S. If someone fired a shot overhead when an intruder was holding up their antique store - the bullet would likely stay lodged in the ceiling or upper part of the structure -- not return to earth!!!

[/offtopic]

 

[ERNIEB]

<font color=blue>You don't hear about dozens of women and children being killed when you have a heavy hailstorm ... quite a few of those hailstones are of that size.</font color=blue>
I was thinking of that awhile back when we had a hail storm with some about baseball size. I saw on the news a woman had stuck her head out of the door to see if they were hitting her car, that was parked in the street. You guessed it, she caught one right on the melon.
While she was interviewed she had a bandage around her head, but was alive, and seemed alert, and as intelligent as any person who would stick their head out during a hail storm.


Ernie

 

[Bird]

<font color=blue>as intelligent as any person who would stick their head out during a hail storm.</font color=blue>

That bad, huh? I love it./w3tcompact/icons/laugh.gif/w3tcompact/icons/laugh.gif

Bird

 

[Anonymous Poster]

This was on tonight's news:

One report said the police suspect a "falling bullet" out of the sky...

Woman Shot In Head During Fireworks Display

{has anyone been doing any experimenting lately on your bullet theories...?}

 

[JOR_EL]

Hi RPM, /w3tcompact/icons/smile.gif

[[[I seriously doubt it would reach 400 fps. Air resistance etc. is a considerable factor on a small body. It might reach that speed in a vacuum ...

You don't hear about dozens of women and children being killed when you have a heavy hailstorm ... quite a few of those hailstones are of that size.]]]

Size is not the issue, DENSITY is! /w3tcompact/icons/wink.gif (Leaving aside the matter of shape, ...which is also a factor.)

The density of lead (the bullet) is ball-parkishly TEN TIMES that of water(the hailstone), ... apprx. 600(or maybe even more, no reference handy) vs 60 lbs./cu. ft.
Actually, due to freezing-expansion, the "ice" bullet has even LESS density that an equal-size(volume) raindrop.

A too-simple analogy to illustrate the point: A feather that weighs X-grains (ostrich?), will fall (and therefore impact your head) at a much slower rate than a lead ball of the same (x-grains) weight.

With a less-dense material OF THE SAME WEIGHT, there is more surface area upon which the "drag" (air resistance) works, ...therefore more "slowing" of the object, in opposition to an equal accelerating force(gravity, in this case).

You have my permission to drop a pound of ostrich-feathers (loose ones, not compressed, mind you) on my head from 10,000 feet overhead. In the case of a pound of lead, however, I'd prefer a limit of perhaps 1/4 inch. /w3tcompact/icons/tongue.gif

Much of this has been covered in the many previous posts on this thread.

...still interesting to read further opinion/comment, though /w3tcompact/icons/laugh.gif !

PS: Remember, when you're falling from the top of a tall building, to yell "Free dummy!"

Someone may just run over and catch you /w3tcompact/icons/shocked.gif !!

Larry

 

[RPM]

O.K. - the bullet hit the back of her head. It wasn't coming down vertically - or near vertically. Probably what happened is somebody a good distance away (maybe a mile) discharged their weapon and the bullet hit her.

To simplify, it helps to consider the bullet as having velocity in two directions - horizontal and vertical.

If you were to fire a gun with the barrel horizontal, all the propellant would drive the bullet horizontally. The bullet would be gradually slowed by air resistance - and gravity would slowly pull it to earth (may take hundreds of yards to drop to the ground - slow vertical velocity (gravity), high horizontal (propellant)) At the point the bullet hits the ground it will likely still be traveling with a high horizontal velocity.

If you were to fire a gun directly up, then both gravity and air resistance conspire against the bullet. The bullet temporarily stops at the top of its path before free-falling to the ground. Horizontal velocity is zero (unless there is wind) because you fired directly up. Vertical velocity is just acceleration due to gravity minus air resistance. Air resistance can be a large brake for a small body.

So, when a gun is discharged with the barrel at any angle between these two - you end up with the propellant giving it a vertical velocity (bullet will rise up due to being propelled at and angle and then fall as gravity slows it and takes over) - and a horizontal component (gradually slowed by air resistance - until gravity pulls it to the ground).

This is all a long winded way of saying that whoever the crazy was that fired the gun was not pointing it directly up. Probably pointing it at 45 degrees or thereabouts. The unfortunate girl is lucky she was not killed. If you fire a warning shot, point straight up - it's much safer (unless you are directly under a steel beam, tank of hydrogen or other obvious hazard!!!)

Better yet - don't fire unless you are in a very serious situation. If you then fire your weapon - make it count, you've just radically escalated the situation.

Patrick

 

[patrickg]

Here is some further comment:

As far as anyone I think experienced in these matters knows most if not all of the shots fired in various near eastern celebratory situations (including TV photo ops) in fact are FMJ standard issue. If you care to "check it out" there have been woundings and fatalities attributed to the practice. No it isn't smart but it is a custom.

I can recall many times as a youngster growing up seeing adults (well, breeding age people) shooting rifles, shotguns and pistols into the air on the 4th of July and New Years. I don't think shotguns (with birdshot) are so dangerous fired within say 30 degrees of vertical but the rest is just plain dangerous and stupid. We had a 4 ft 7 in tall neighbor lady with a huge St. Bernard for whom it was a ritual to fire her 12 gauge into the air at the stroke of midnight on New Years or when her watch said it was time. New Years just wasn't complete till she had a blast at it. I recall no one EVER complaining.

Now to the debate: Balistic efficiency and coefficient are greatly influenced by the projectiles cross sectional area, length, density, and of course attitude (going straight or trying to keyhole. Except for spin and attitude (but lets assume a radially symetrical projectile and good rifling), it matters not whether a projectile is dropped from the height it would have obtained by shooting it vertically or shot there and allowed to fall. This would be pretty accurate if it were a lead ball from my 75 cal muzzle loading flintlock pistol/handcanon (smooth bore) or a rifled version. But let's consider a more modern rifle or pistol round.

In the case of shooting straight up the spin would continue until after the projectile reached it's zenith and began to fall back down. Gyroscopic stability would keep it pointed up and falling backward for a while (high draq attitude). As aerodynamic forces and associated turbulence build with increasing downward speed the gyroscopic forces of the residual spin would trigger precession and nutation (largely due to non-symetric vortex shedding) which would further destabilize the projectile and with the system's extreme sensitivity to initial conditions (part and parcel of the application of CHAOS theory to this example) predictability in the micro sense would become impossible. A family of behaviors could be described but the extended downward trajectory and its "terminal velocity" of any particular shot would be impossible to predict. Said another way, you can predict pretty well from experience how long it will take to pop a bag of microwave popcorn but no one can predict when any particular kernel will pop or even if it will pop (Forgive me Orville R.) Still, anything larger than a .22 BB cap or maybe a CB cap would hurt. A Winchester .458 mag would be really dangerous as apparently AK-47 rounds given the number who have died from the practice of celebratory firing.

Wow, I wondered when all those years of math and physics would come in handy again. I'm stoked, man. It isn't everyday someone stops you on the sidewalk and asks about quantum mechanics and isn't talking about a car or someone at the local brake, muffler, and shock shop wants a lecture on under damped, over damped and critically damped mechanical systems. Anybody want to discuss Maxwell's equations, the Poynting vector, tensors, Lorentian contraction the implications if plank's constant isn't???? Huh huh huh???

Patrick

P.S. Due to economic considerations and laziness, I do not have a spill chiquer (or word processor) so please make fun of me, my misunder standing of the oblivious, and so on but kut me sum slak on spilling, OK?

 

[glennmac]

Patrick,

Couldn't you however compute the maximum possible terminal velocity of a particular bullet by assuming a spherical bullet of the same mass and density. The spherical shape should avoid or minimize the nutation, precession, vortex shedding and gyroscopy, as well as cavitation and ecdysiasm. Thus a maximum terminal velocity could be established. It should then be easy for Johnny Cochrane to demonstrate whether a the bullet traveling at its maximal terminal velocity can penetrate the skin or skull. "If the skin don't split, you must acquit."

 

[kerr]

What you said! Breeding age ha ,very good!

 

[JOR_EL]

Glenmac, /w3tcompact/icons/smile.gif

[[[ "If the skin don't split, you must acquit." ]]]

Does it then follow (thinking in lawyer-ese, of course) that a pillow-over-the-face smother-murderer must go free?

Larry /w3tcompact/icons/wink.gif