A link to some basic flechette info:
A link to some basic flechette info:
Funny story, true:
I was in my first year at the Univ or Arizona, and was taking an intro level mechanics course. The instructor was doing a simple problem like this, which of course neglected any air friction effects.
He solved it and got the answer, and then as an aside, said, "of course this is all wrong. The resistance of the air on the projectile is complicated, it goes like the fourth power (IIRC) of the velocity. Which one of you can tell me why I know this?"
The class was very small and it had come out that he had worked in the shah's army in iran. So I took a SWAG and piped up, "because you were an artillery officer."
"Correct."
Jim
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32 = 33 for large values of 32.
:)
Jim
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Greetings and Salutations.
On Tue, 16 Dec 2003 03:45:12 GMT, snipped-for-privacy@hotmail.com (Roy) wrote:
As a matter of fact, the show "Mythbusters" took on this very thing just the other day. The results were that the penny, if it made it PAST those structures, would hit hard enough to bounce, but would not only NOT damage the concrete, but likely would only have (at most) bruised a person if it hit them. Yea...they tested that too, by sticking their hand in the path of the penny (Never said these guys were BRIGHT, after all). They used a modified pneumatic nail gun to get the velocity on the penny. I seem to remember it was a Senco...but, I am really not sure. In any case, it was an interesting show. Actually, I have to throw in a plug for the show, in general. These guys do seem to have a clue about what they are doing, and they fabricate some interesting stuff (often out of metal) to test their theories. One of the recent shows also had them building a cannon from a tree trunk (OMWC - Blacksmith making hoops for strength and applying them hot). The myth was that this German town had made a cannon overnight, to repel the invaders, but, it blew up on them with the first shot, killing many townsfolk. The results, by the by, were that the mythbusters came to the conclusion that there was NO way that the townsfolks could have cored a tree trunk that was eight feet or more long in a night. With hand augers, they only got a few inches down after much struggling. They ended up using a Hole Hawg to run the rest of the hole. On the other hand, they only managed to destroy the cannon by packing it with WAY too much powder - I forget how much, but, it was up at 20 lbs (of black powder) or more. It fired pretty well with smaller loads, though. Regards Dave Mundt
The point I was trying to make was that it is possible that a head wound may require much less energy than a torso wound to be fatal and that the higher the trajectory is, the more likely a head wound is.
Mark Rand RTFM
Ted sez: "32 ft/sec^2 "near" Earth's surface in vacuum"
Forget the vacuum, Ted. Acceleration is independent of ambient conditions.
*Terminal velocity* is related to the medium through which a body "accelerates". Acceleration varies slightly with altitude (on earth) with 32 ft sec-sec being the accepted figure for sea level.Bob Sw>
Acceleration depends on the force and the mass (a = f/m). The net force is the force from gravity minus the drag from the air. Obviously at the terminal velocity the acceleration is zero.
Best regards, Spehro Pefhany
I think the vast majority of gun owners in the U.S. believe the same. If you exclude the gang banger types, the drunken idiot types and the crack head types, you get an amazing firearm safety record in this country. The same can be said for driving, flying and other activities that have the potential to harm others.
JTMcC.
>
This same web site that Ed quoted does have info on "falling bullets" at
Lane
Did they claim *that* one was untrue?
My tuchstone of truth for such things has always been
Happy Holidays,
Jeff
-- Jeff Wisnia (W1BSV + Brass Rat '57 EE)
"If you can keep smiling when things go wrong, you've thought of someone to place the blame on."
Anyone have access to this report?
Falling Bullets: Terminal Velocities and Penetration Studies - by Lucien C. Haag It is mentioned here:
It supposedly says: "As a point of interest a velocity of about between 160 and 200 f/s (±) is needed to penetrate skin."
Lane
120 mph is about right... you can vary it a good bit by body position though... maybe 110 or a little under by 'getting big', and push 200 by getting vertical and 'small'.
As I recall, it takes about 11 seconds, and 1,300 feet to reach terminal in a relaxed 'frog' position. (This is what I recall, don't hold me to it, if anyone's interested I'll look it up in some old jumping books.)
There is a rec.skydiving newsgroup too... mostly shuck & jive though.
Skydiving is about all I did in the 70's... it's a lot of fun really. Most of the he-man super dangerous aspect was pretty much gone by the time started, and they've come a long way since then.
Erik
This was mentioned a few years back on the Compuserve Firearms Forum, & one of the members who also happened to be a free fall sky diver as well as a shooter undertook some experiments. He dropped various bullets from both handguns & rifles, just as he left the plane. In all cases he was easily able to overtake the bullets. Dropping bullets, even pushing them downwards when in free fall were similarly overtaken once he adopted a dive position. So, anybody killed must almost certainly be from bullets fired not "straight up" , but at some shallower angle.
Perhaps noone told the Klansman to hold the brown bit, not the blued bit?
----------------------------------------------------------------------------------------------------- snipped-for-privacy@boltblue.com John Lloyd - Cymru/Wales
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How about a 16inch round from USS New jersey
----------------------------------------------------------------------------------------------------- snipped-for-privacy@boltblue.com John Lloyd - Cymru/Wales
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Just because they couldn't do it doesn't mean it can't be done. In our machine era we have forgotten some of the old hand methods that worked pretty well. Hand augers aren't necessarily the right tools to use. The cutters used for making wooden water pipes would have gone much faster, I think. They would have to. Or no one would have ever made a second section of pipe.
John Martin
"As Larry and his lawnchair drifted into the approach path to Long Beach Municipal Airport, perplexed pilots from two passing Delta and TWA airliners alerted air traffic controllers about what appeared to be an unprotected man floating through the sky in a chair."
Damn I wish they had saved the tapes of those conversations between the controllers and the flight crews. Now *that* would be priceless stuff.
My grandfather was fascinated by this event. We have a photo of him on his 90th birthday, sitting in our yard in an aluminum lawn chair. With about 20 helium balloons tied to it!
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Maybe this will convince some that the velocity of an object hitting the ground, after being sent up high, doesn't depend at all on the velocity at which it left the ground.
I wan't trying to be morbid, only to provide an example that would help clear up that point. Thanks.
Ed Huntress
Hello, John. Weren't you there as far back as the early '90s?
Ed Huntress
Spehro Sez: "Acceleration depends on the force and the mass (a = f/m). The net force is the force from gravity minus the drag from the air. Obviously at the terminal velocity the acceleration is zero."
A fine point for sure! But acceleration is, as you said = force/mass. Not sure if you meant to say that air drag has an influence on acceleration from the force of gravity. I don't think it does. Air drag will effect the resulting velocity, but acceleration from gravity is a constant.
Bob Swinney
But I was told by a former high-rise construction worker that a bolt dropped from an upper floor on a supervisor walking on the ground floor can do some damage.
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