On 15 Dec 2003 23:56:42 -0500, (DoN. Nichols)
wrote:

In article ,
Dan Thomas wrote:

In World War I the French used "flechettes" against the troops in
the trenches. These were machined steel darts a few inches long, with
flutes cut into the aft end to stabilize and rotate them. They were
dropped from airplanes at a considerable height, hundreds at a go, and

[ ... ]

Increasing drag at lower altitudes would slow the acceleration, but a
much higher final velocity should be possible for a dart.

One factor is that the mass vs cross-sectional area was
seriously better than the average bullet, thanks to the additional
length, and the the stabilization of the fins, to keep the streamlined
and small cross section end pointed in the direction of flight. The
cross section would (approximately) define the drag, and the mass would
determine the acceleration force due to gravity. So -- as long as you
could keep it stabilized, the longer the dart, the higher the terminal
velocity.

Given stabilization -- a one-foot length of rebar would be
significantly more dangerous than a .50 cal bullet.

Thors Hammer was a Star Wars concept in which a 10' or longer chunk of
steel and composit with steering jets was to be used as a tank killer
from low orbit. IRRC

Out of curiosity -- what was the altitude ceiling for WW-I
period aircraft? (And for the pilots, since they almost certainly did
not have bottled oxygen available at that time.) IIRC, the air force
wanted the WW-II period pilots to be on oxygen at 10,000 feet or higher.

Enjoy,
DoN.

Just finished Rickenbackers book about his flying Spads etc in WW1. He
mentioned 15-20,000 feet. Seemed a bit high for no O2..but he did say
it.

Gunner

" ..The world has gone crazy. Guess I'm showing my age...
I think it dates from when we started looking at virtues
as funny. It's embarrassing to speak of honor, integrity,
bravery, patriotism, 'doing the right thing', charity,
fairness. You have Seinfeld making cowardice an acceptable
choice; our politicians changing positions of honor with
every poll; we laugh at servicemen and patriotic fervor; we
accept corruption in our police and bias in our judges; we
kill our children, and wonder why they have no respect for
Life. We deny children their childhood and innocence- and
then we denigrate being a Man, as opposed to a 'person'. We
*assume* that anyone with a weapon will use it against his
fellowman- if only he has the chance. Nah; in our agitation
to keep the State out of the church business, we've
destroyed our value system and replaced it with *nothing*.
Turns my stomach- " Chas , rec.knives

On Tue, 16 Dec 2003 00:17:57 -0600, "Bill Bright"
wrote:


"George E. Cawthon" wrote in message
...


Eastburn wrote:

Tim -

Have you ever seen a softball sized hail that falls - smashes roofs to
junk
and puts deep bends in cars.

Then there is the smaller stuff that are golf ball size that knocks out
people
left and right.

I suspect you are talking about pea size or rice size. Yea - that is
almost like snow.

Martin
--
Martin Eastburn, Barbara Eastburn
@ home at Lion's Lair with our computer
NRA LOH, NRA Life
NRA Second Amendment Task Force Charter Founder

I think you will find that softball size and probably golf
ball size hail often has much more energy than the terminal
velocity of a falling rifle bullet. By the way, nobody
mentioned pistol bullets. Although they often weight more
than rifle bullets, pistol are much less aerodynamic than
rifle bullets and would not achieve as high a terminal
velocity and would cause less damage than a pointed rifle
bullet.

It would be hard to tell, because a rifle bullet is not going to be spin
stableized any more. It would start falling base to earth until the wind
resistance hitting the flat base would start it tumbling. Now if the bullet
shape had the center of gravity foward of the tip to base center point, then
it would fall stable pointy end down and have a very high terminal velocity

Why wouldnt it be spin stablized? Granted there are some rotational
friction forces (skin layer) slowing it down, including air pressure
against the meplat and base going up and down..but give rotational
speeds of the common bullet are in excess of 100,000 rpm...... it
would take a lot to slow it down.

Gunner

" ..The world has gone crazy. Guess I'm showing my age...
I think it dates from when we started looking at virtues
as funny. It's embarrassing to speak of honor, integrity,
bravery, patriotism, 'doing the right thing', charity,
fairness. You have Seinfeld making cowardice an acceptable
choice; our politicians changing positions of honor with
every poll; we laugh at servicemen and patriotic fervor; we
accept corruption in our police and bias in our judges; we
kill our children, and wonder why they have no respect for
Life. We deny children their childhood and innocence- and
then we denigrate being a Man, as opposed to a 'person'. We
*assume* that anyone with a weapon will use it against his
fellowman- if only he has the chance. Nah; in our agitation
to keep the State out of the church business, we've
destroyed our value system and replaced it with *nothing*.
Turns my stomach- " Chas , rec.knives

JTMcC wrote:
"ATP" wrote in message
news
JTMcC wrote:
"jim rozen" wrote in message
...
In article , JTMcC says...

I would think the effect of gravity
and wind resistance would determine the maximun velocity of the
falling bullet

The phrase is 'terminal velocity' and I suspect that for
any modern round fired straight up, this is indeed the
determining factor, so I would put my guess in line with
yours. As you suggest, there are others here who truly
know the answer off the top of their heads.

Jim

I'm aware of terminal velocity, and have reached it a time or two. I
can reach it while falling from a height, regardless of my velocity
in reaching that height, therefor my difference of opinion with the
post about the bullet dropping at the same speed it initially rose.
I can jump (fall, be pushed out of) an airplane at a height of 1000
ft and I will achieve a certain speed before wind resistance
prevents any further increase. I can also be shot from a cannon
straight into the air, or simply step off a platform at 1000 feet
and still, my velocity toward the earth is limited by drag. If I
spend 7 hours climbing to the 1000 foot mark, or ascend in a matter
of seconds via F-16, my upward velocity matters not to the downward
velocity I attain. That is my take, but then I wasn't even paying
attention in H.S. physics.

JTMcC.

You are right that it does not matter how you get there, but the
initial velocity does matter in projectile motion problems. That is
the only energy the projectile has, and it will be converted into a
higher potential energy until it has zero kinetic energy at the very
top. Putting aside air resistance, initial velocity and elevation is
all we need to determine the maximum height the projectile will
reach. There are several ways the problem can be solved, but
comparing energy states is probably the most intuitive.

We don't care how high it goes, we only care about it's velocity
returning to earth, after coming to a theoretical stop after being
fired straight up. We are talking about bullets with no energy
remaining from the initial firing.

No kinetic energy remaining, they have potential energy due to their
increased height, relative to some lower height. The potential energy is
proportional to the height.


I can go out in my fromt yard
right now, and fire a .22 caliber, 55 grain projectile into the sky
at around 2800 fps (feet per second) or over 4000 fps. Using my
original criteria of the bullet flying straight up, until stopped by
the force of gravity, and returning to earth via the same
gravitational force, do you really believe the bullet fired from a
220 Swift or 22-250 will hit the ground at a greater speed than the
one fired from a .223? Again, I was more interested in the girl
sitting next to me in H.S. physics class than the math problems, but
I'm still pretty sure I'm right.

JTMcC.

If you are considering air resistance, any bullet fired up is going to have
sufficient kinetic energy and attain a sufficient height to return at
terminal velocity. We have to either simplify the problem by neglecting air
resistance or consider all factors, which would get pretty complicated. In
any case, energy is conserved and theoretically can all be accounted for, in
terms of heat, work done on the greater environment, etc.. As far as physics
class, the important thing in any lab class is to snag a decent looking girl
as a lab partner early on...

TSJABS wrote:
by a bullet that
was shot into the air.

Funny but that seems to be where most bullets end up getting fired.
If I recall wasen't one of the klan members either in a tree or up on
a stand and the goof with the gun wasen't aiming exactly straight up.

A bullet fired exactly straight up will finally come to 0 speed at
which it will break over and start excellerating to terminal
velocity. Here in the midwest we frequently have hail that exceeds
the size of many bullets and fall from much greater heights and its
funny how people can just walk around in it and not get killed.
I think a person would be suprised how many "accidental" shooting
are blamed on "I just shot the gun straight into the air" sydrome.

tim

The article didn't give a lot of details, it was an initiation, they were
shooting a guy with paintball guns and someone fired the real gun to provide
sound effects. Daniel Carver didn't approve.

Regardless of weight, a falling body will accelerate at 33 ft. per second,
per second.

In article , JTMcC says...

.223? Again, I was more interested in the girl sitting next to me in H.S.
physics class than the math problems, but I'm still pretty sure I'm right.

I think gunner has already stated that the terminal velocity
for common commercial shell sizes is way, way far below
the muzzle velocity. This says you are right in my book.

Jim

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In article , Gunner says...

Just finished Rickenbackers book about his flying Spads etc in WW1. He
mentioned 15-20,000 feet. Seemed a bit high for no O2..but he did say
it.

Need to put the engines on O2 as well - I think none of
the ww1 vintage aircraft had turbochargers - that was
probably the limiting factor for useable altitude.

Jim

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==================================================

JHC the snow flakes must really come down fast wherever you're from.

Pablo wrote:

Regardless of weight, a falling body will accelerate at 33 ft. per second,
per second.

"JTMcC" wrote in message
news
We don't care how high it goes, we only care about it's velocity returning
to earth, after coming to a theoretical stop after being fired straight
up.
We are talking about bullets with no energy remaining from the initial
firing. I can go out in my fromt yard right now, and fire a .22 caliber,
55
grain projectile into the sky at around 2800 fps (feet per second) or over
4000 fps. Using my original criteria of the bullet flying straight up,
until
stopped by the force of gravity, and returning to earth via the same
gravitational force, do you really believe the bullet fired from a 220
Swift
or 22-250 will hit the ground at a greater speed than the one fired from a
.223? Again, I was more interested in the girl sitting next to me in H.S.
physics class than the math problems, but I'm still pretty sure I'm right.

JTMcC.

As an aside I should add that I don't and wouldn't fire into the air, as
I've allways told my kids, you are personally responsible for every round
you fire. Period.

regards,
JTMcC.

JTMcC wrote:

"JTMcC" wrote in message
news
We don't care how high it goes, we only care about it's velocity returning
to earth, after coming to a theoretical stop after being fired straight
up.
We are talking about bullets with no energy remaining from the initial
firing. I can go out in my fromt yard right now, and fire a .22 caliber,
55
grain projectile into the sky at around 2800 fps (feet per second) or over
4000 fps. Using my original criteria of the bullet flying straight up,
until
stopped by the force of gravity, and returning to earth via the same
gravitational force, do you really believe the bullet fired from a 220
Swift
or 22-250 will hit the ground at a greater speed than the one fired from a
.223? Again, I was more interested in the girl sitting next to me in H.S.
physics class than the math problems, but I'm still pretty sure I'm right.

JTMcC.

As an aside I should add that I don't and wouldn't fire into the air, as
I've allways told my kids, you are personally responsible for every round
you fire. Period.

regards,
JTMcC.

Yes......but you have a brain.

"Roy" wrote in message
...
I have heard on numerous occasion that a penny thrown off the top
observation tower of thr Empire State building can hit the ground with
enough force to crack a 6" concrete slab. I used to believe this
statement when I was a kid, but have a hard time buying it as fact
now. I just can't see it being fact, and see it more of an old wives
type tale. I don;t really think you could throw a penny that hard and
far enough to make it reach out sufficiently to clear the lower floors
stepped out structure anyhow.


A month or so ago, the MythBusters on the Discovery Channel tested the penny
legend and determined that the terminal velocity of a penny tossed off the
Empire state Bldg was about 60 MPH, as I recall. There is not enough
kinetic energy in a penny at that speed to do much damage.

Randy

No, I'm not mistaken about a "little slower". This is a relative term
with wide variation in value; in other words, I have not done the
calculations but the velocity will be slower.
If you real want the velocity of the bullet apply the following:

(1) v = v(0)+at
(2) x = x(0)+1/2(v(0)+v)t
(3) x = x(0)+v(0)t+ 1/2at^^2
(4) v^^2 = v(0)^^2 + 2a(x-x(0))

Also note that these calcuations (from Physics 101; Halliday and
Resnick/Wiley and Sons Inc) do not include atmospheric losses.

have fun.
S. Evan

JTMcC wrote:

"SimonShabtai Evan" wrote in message
...

This is basic physic 101. In a vacuum the bullet will return to the
firing point at the same velocity. In air a little slower but lethal
not the less.
S. Evan


We aren't living in a vacume around here. I believe you are misstaken when
you say a "little" slower.


JTMcC.



JTMcC wrote:


"Chris Oates" none wrote in message
...


"Dean" wrote in message
...


This is sort of metalwork - it involves lead. I was watching the

Iraqies

celebrating the capture of Saddam by firing their rifles and guns into


the


air. How dangerous are the bullets coming down ? I know they fall back


much


slower than they leave the gun barrel, but they must still be doing a


fair


clip. They said 4 people so far have been killed by this but I guess in


Iraq


its hard to know which bullets came from where. As a few of you know


about


guns I thought I'd ask here.


Yes, same velocity they went up with



That sure doesn't sound right to me. A bullet or any other object fired

into

the air, let's say straight up to keep it simple, will slow until it

finally

stops and begins to fall back to earth. I would think the effect of

gravity

and wind resistance would determine the maximun velocity of the falling
bullet (object), not the velocity at which it was fired upward with. The
same speed would be realized as if you had simply dropped the bullet
(object) at the same altitude from a hot air balloon. Feel free to

correct

me if I'm wrong.

JTMcC.




many cases on manslaughter have resulted
damage can be nasty as the bullet may have
aquired a spin or not be in line with the fall

On Tue, 16 Dec 2003 00:17:57 -0600, "Bill Bright" wrote:
It would be hard to tell, because a rifle bullet is not going to be spin
stableized any more. It would start falling base to earth until the wind
resistance hitting the flat base would start it tumbling. Now if the bullet
shape had the center of gravity foward of the tip to base center point, then
it would fall stable pointy end down and have a very high terminal velocity

No. As Hatcher reported, the army tests showed the bullets were still
spin stablized when they came down (base first). You have to realize
that a .30 bullet leaves the muzzle spinning nearly 200,000 RPM. Even
after gravity has slowed its upward velocity to zero, it is still spinning
at an incredible rate. So gyroscopic forces easily overcome any aerodynamic
tendency for it to nose over and come down point first.

Gary

"SimonShabtai Evan" wrote in message
...
No, I'm not mistaken about a "little slower". This is a relative term
with wide variation in value; in other words, I have not done the
calculations but the velocity will be slower.
If you real want the velocity of the bullet apply the following:

(1) v = v(0)+at
(2) x = x(0)+1/2(v(0)+v)t
(3) x = x(0)+v(0)t+ 1/2at^^2
(4) v^^2 = v(0)^^2 + 2a(x-x(0))

Also note that these calcuations (from Physics 101; Halliday and
Resnick/Wiley and Sons Inc) do not include atmospheric losses.

have fun.
S. Evan

Tumbling which way? Bullets tumble when they lose a percentage of their rpm.
Bullets shot straight up always tumble. There go the old aerodynamics...

FWIW, before WWII the US Army tested .30 cal military bullets shot straight
up. They returned to Earth at a velocity of 200 - 220 mph. It didn't matter
how high they were shot, what their initial muzzle velocity was, etc.

Specific sectional density doesn't matter much. Aerodymanics go out the
window once they start to tumble. What matters is their mass relative to
*effective* projected cross-sectional area, times some factor also related
to mass. This is a backhanded way of getting at the Reynolds number for a
given-size bullet. The "effective" area is a factor of shape and the way it
tumbles.

I understand that the terminal velocity of a spread-eagled human is
something like 120 mph. It doesn't matter if you fall from 2,000 feet or
50,000 feet, you hit the ground at around 120 per. Does anyone have better
data on that?

Ed Huntress

There aren't any decent looking females in the physics classes. That's
why I played hooky in the Bio-chem. labs. Blonde, great curves,
friendly, Berkeley coeds....wow 8-)
S. Evan

ATP wrote:

JTMcC wrote:

"ATP" wrote in message
news
JTMcC wrote:

"jim rozen" wrote in message
...

In article , JTMcC says...


I would think the effect of gravity
and wind resistance would determine the maximun velocity of the
falling bullet

The phrase is 'terminal velocity' and I suspect that for
any modern round fired straight up, this is indeed the
determining factor, so I would put my guess in line with
yours. As you suggest, there are others here who truly
know the answer off the top of their heads.

Jim

I'm aware of terminal velocity, and have reached it a time or two. I
can reach it while falling from a height, regardless of my velocity
in reaching that height, therefor my difference of opinion with the
post about the bullet dropping at the same speed it initially rose.
I can jump (fall, be pushed out of) an airplane at a height of 1000
ft and I will achieve a certain speed before wind resistance
prevents any further increase. I can also be shot from a cannon
straight into the air, or simply step off a platform at 1000 feet
and still, my velocity toward the earth is limited by drag. If I
spend 7 hours climbing to the 1000 foot mark, or ascend in a matter
of seconds via F-16, my upward velocity matters not to the downward
velocity I attain. That is my take, but then I wasn't even paying
attention in H.S. physics.

JTMcC.


You are right that it does not matter how you get there, but the
initial velocity does matter in projectile motion problems. That is
the only energy the projectile has, and it will be converted into a
higher potential energy until it has zero kinetic energy at the very
top. Putting aside air resistance, initial velocity and elevation is
all we need to determine the maximum height the projectile will
reach. There are several ways the problem can be solved, but
comparing energy states is probably the most intuitive.

We don't care how high it goes, we only care about it's velocity
returning to earth, after coming to a theoretical stop after being
fired straight up. We are talking about bullets with no energy
remaining from the initial firing.


No kinetic energy remaining, they have potential energy due to their
increased height, relative to some lower height. The potential energy is
proportional to the height.


I can go out in my fromt yard

right now, and fire a .22 caliber, 55 grain projectile into the sky
at around 2800 fps (feet per second) or over 4000 fps. Using my
original criteria of the bullet flying straight up, until stopped by
the force of gravity, and returning to earth via the same
gravitational force, do you really believe the bullet fired from a
220 Swift or 22-250 will hit the ground at a greater speed than the
one fired from a .223? Again, I was more interested in the girl
sitting next to me in H.S. physics class than the math problems, but
I'm still pretty sure I'm right.

JTMcC.


If you are considering air resistance, any bullet fired up is going to have
sufficient kinetic energy and attain a sufficient height to return at
terminal velocity. We have to either simplify the problem by neglecting air
resistance or consider all factors, which would get pretty complicated. In
any case, energy is conserved and theoretically can all be accounted for, in
terms of heat, work done on the greater environment, etc.. As far as physics
class, the important thing in any lab class is to snag a decent looking girl
as a lab partner early on...

"Gary Coffman" wrote in message
...
On Tue, 16 Dec 2003 00:17:57 -0600, "Bill Bright"
wrote:
It would be hard to tell, because a rifle bullet is not going to be spin
stableized any more. It would start falling base to earth until the wind
resistance hitting the flat base would start it tumbling. Now if the
bullet
shape had the center of gravity foward of the tip to base center point,
then
it would fall stable pointy end down and have a very high terminal
velocity

No. As Hatcher reported, the army tests showed the bullets were still
spin stablized when they came down (base first).

I don't think so, although it's been many years since I read the research. I
thought they were tumbling.

Ed Huntress

wrote:
Ted Edwards wrote:

Bob Swinney wrote:
Fire a cannon ball exactly horizontal (level) with the earth. At the exact
instant the cannon ball leaves the muzzle, drop another cannon ball from the
same height. The 2 cannon balls will reach the earth at the same time.

On an airless planet but not on Earth. Think Areodynamic drag.

Even on earth.

Nope.

Basic physics has us break things up into components.

This is frequently the case and examples in high school Physics have
carefully chosen conditions so this will be ok. In order to do so, we
apply the principle of superposition which requires that the total
effect of a set of forces is the sum of the effects of the individual
forces. This requires linearity. Drag is proportional to velocity
squared.

Set up the differential equations of motion for a projectile fired at
some angle to the horizontal in a vertical gravitational field and
experiencing a retarding force alligned with but in opposite direction
to the motion vector that is proportional to the magnitude of the
velocity squared. It's a neat problem and fun to work. (I first did it
studying arrow flight.) You will discover two things: 1) The resulting
set of differential equations has no closed form solution (elliptic
integrals) and must therefore be solved numerically. (Runge-Kutta is a
good method if you wish to try it.) 2) Attempting to separate the
forces into vertical and horrizontal components gives an approximation
of variable quality but is, in fact, wrong. Speaking vaguely, since the
aerodynamic forces depend on the square of velocity, a change in
horizontal velocity affects vertical as well as horizontal force and
vice versa.

Ted

Pablo wrote:

Regardless of weight, a falling body will accelerate at 33 ft. per second,
per second.

32 ft/sec^2 "near" Earth's surface in vacuum.

Ted

"Gary Coffman" wrote in message
...

No. As Hatcher reported, the army tests showed the bullets were still
spin stablized when they came down (base first).

BTW, if you find this entertaining, here's some newer data, based on Doppler
radar research:

http://www.nennstiel-ruprecht.de/bullfly/anom.htm

Ed Huntress

"SimonShabtai Evan" wrote in message
...
No, I'm not mistaken about a "little slower". This is a relative term
with wide variation in value; in other words, I have not done the
calculations but the velocity will be slower.
If you real want the velocity of the bullet apply the following:

(1) v = v(0)+at
(2) x = x(0)+1/2(v(0)+v)t
(3) x = x(0)+v(0)t+ 1/2at^^2
(4) v^^2 = v(0)^^2 + 2a(x-x(0))

Also note that these calcuations (from Physics 101; Halliday and
Resnick/Wiley and Sons Inc) do not include atmospheric losses.

FWIW Frictional losses are very significant at high velocities(i.g. shuttle
reintry). When I was in infantry school at Ft. Jackson during the last
'action' in S.E. Asia I had an opportunity to get one of those info cards
that came in each case of 50 cal. machine gun ammo. On that card, range,
angle, velocity data were given WITH atmospheric effects. If I just used
the equations listed above and optimum 45 deg angle I calculated the range
of the 50 cal. to be IIRC miles but the tables showed about 20% what I
calculated w/o allowances for air resistance. If one is really interested
in this stuff you might look at some of the work Galileo(1564-1642) did with
cannon trajectories years before Newton(1642-1727) Just Google _Galileo
projectile motion_ or some such.
Larry

"George E. Cawthon" wrote in message ...
Dan Thomas wrote:
In World War I the French used "flechettes" against the troops in
the trenches. These were machined steel darts a few inches long, with
flutes cut into the aft end to stabilize and rotate them. They were
dropped from airplanes at a considerable height, hundreds at a go, and
would reach transsonic speeds (one source claimed supersonic speeds,
but I think the drag would preclude that)before they hit the ground or
some unfortunate soldier. Helmets weren't much protection; they were
sharp.
The density of air at 18,000 feet is half of that at sea level.
Anything dropped from this altitude is going to accelerate much more
quickly, as drag is a function of the square of any increase in speed.
Half of the density should, I figure, cut the drag to a quarter.
Increasing drag at lower altitudes would slow the acceleration, but a
much higher final velocity should be possible for a dart.

Dan

You might be surprised about how low the terminal speed
would be, but without any data there is no point in
speculation. You did say the they were several inches long
so they would weight much more than a bullet and with a
point they could possibly have penetrated a helmet. In
comparison, it is highly unlikely that a 150 grain bullet
traveling at 300 fps would penetrate a helmet, just a dent.
Weight is everything at low speeds, an arrow shot into the
sky and falling down could penetrate you because of it's
much greater weight.


A link to some basic flechette info:
http://en.wikipedia.org/wiki/Flechettes

Other links pointed out the modern use of flechettes fired from
guns, in canisters, in Vietnam and Israel. These are much smaller,
maybe an inch or so.
I couldn't find a link giving terminal velocity for the WWI
variety, but there must be something online somewhere.
Dan

In article dtIDb.370160$Dw6.1208036@attbi_s02, Lawrence L'Hote says...

FWIW Frictional losses are very significant at high velocities(i.g. shuttle
reintry). When I was in infantry school at Ft. Jackson during the last
'action' in S.E. Asia I had an opportunity to get one of those info cards
that came in each case of 50 cal. machine gun ammo. On that card, range,
angle, velocity data were given WITH atmospheric effects. If I just used
the equations listed above and optimum 45 deg angle I calculated the range
of the 50 cal. to be IIRC miles but the tables showed about 20% what I
calculated w/o allowances for air resistance. If one is really interested
in this stuff you might look at some of the work Galileo(1564-1642) did with
cannon trajectories years before Newton(1642-1727) Just Google _Galileo
projectile motion_ or some such.

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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In article , Ted Edwards says...

Regardless of weight, a falling body will accelerate at 33 ft. per second,
per second.

32 ft/sec^2 "near" Earth's surface in vacuum.

32 = 33 for large values of 32.



Jim

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==================================================

Greetings and Salutations.

On Tue, 16 Dec 2003 03:45:12 GMT, (Roy) wrote:

I have heard on numerous occasion that a penny thrown off the top
observation tower of thr Empire State building can hit the ground with
enough force to crack a 6" concrete slab. I used to believe this
statement when I was a kid, but have a hard time buying it as fact
now. I just can't see it being fact, and see it more of an old wives
type tale. I don;t really think you could throw a penny that hard and
far enough to make it reach out sufficiently to clear the lower floors
stepped out structure anyhow.

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

On Tue, 16 Dec 2003 00:59:12 GMT, "Bob Swinney" wrote:

Mark sez: "Notwithstanding Gunners report i would suggest that a bullet
falling
vertically is more likely to cause a head injury than one moving with a
lower
trajectory. The Army estimates for energy required to inflict a mortal
wound
were probably not specific to head wounds. If the bullet has enough energy
to
penetrate the skull, then it probably has enough energy to cause a fatal
wound."

Hmmnnnn? I wonder about that. Without doing the ballistic research thing,
it would seem that a bullet moving with any trajectory at all would still
have a remaining horizontal component of velocity. Thus, I believe the
lower trajectory bullet, i.e., stray bullet, would be the more dangerous.

Bob Swinney




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 Swinney

"Ted Edwards" wrote in message
...
Pablo wrote:

Regardless of weight, a falling body will accelerate at 33 ft. per
second,
per second.


Ted

(Roy) wrote in message .. .
I have heard on numerous occasion that a penny thrown off the top
observation tower of thr Empire State building can hit the ground with
enough force to crack a 6" concrete slab. I used to believe this
statement when I was a kid, but have a hard time buying it as fact
now. I just can't see it being fact, and see it more of an old wives
type tale. I don;t really think you could throw a penny that hard and
far enough to make it reach out sufficiently to clear the lower floors
stepped out structure anyhow.

When I used to work for a living,we had a hangers airconditioning unit
get a bullet hole in it. It was highly unlikely someone shot the AC
from a aircraft, but down the road was a pretty bad section of town
and gunshots could often be heard. We figured a shot was fired in the
air and it came down and went through the AC units fan blade and
compressor housings top.
Visit my website: http://www.frugalmachinist.com
Opinions expressed are those of my wifes,
I had no input whatsoever.
Remove "nospam" from email addy.


Mythbusters on History Channel did this just a few weeks ago. They
figured out the terminal velocity of a penny wasn't enough to hurt
much, modified a staple gun to shoot pennies at the terminal velocity,
didn't even raise much of a welt when one of them finally tried it on
himself. On the other hand, they showed the ledge 5 stories down from
the top of the Empire State Building, it had quite a few pennies on
it. Kind of makes you wonder what some people are thinking...

If you guys haven't caught Mythbusters, it's about debunking urban
myths. Some of the stuff that's shown so far has been about the guy
in the lawn chair and the weather balloons, making a cannon out of a
tree trunk(it worked), getting painted gold all over ala James Bond
movie, peeing on the third rail, flushing flammable liquids and
getting an exploding toilet and one of my favorites, the exploding
frozen biscuits in the hot car(they did). I missed the episode about
the JATO unit and the Chevy. It's on Fridays. Loads of metalworking
content(lots of ballistic gelatin, too).

Stan

On Tue, 16 Dec 2003 19:43:23 GMT, the renowned "Bob Swinney"
wrote:

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.

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
--
"it's the network..." "The Journey is the reward"
Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com

"Eddy" wrote in message
...


JTMcC wrote:

"JTMcC" wrote in message
news
We don't care how high it goes, we only care about it's velocity
returning
to earth, after coming to a theoretical stop after being fired
straight
up.
We are talking about bullets with no energy remaining from the initial
firing. I can go out in my fromt yard right now, and fire a .22
caliber,
55
grain projectile into the sky at around 2800 fps (feet per second) or
over
4000 fps. Using my original criteria of the bullet flying straight up,
until
stopped by the force of gravity, and returning to earth via the same
gravitational force, do you really believe the bullet fired from a 220
Swift
or 22-250 will hit the ground at a greater speed than the one fired
from a
.223? Again, I was more interested in the girl sitting next to me in
H.S.
physics class than the math problems, but I'm still pretty sure I'm
right.

JTMcC.

As an aside I should add that I don't and wouldn't fire into the air, as
I've allways told my kids, you are personally responsible for every
round
you fire. Period.

regards,
JTMcC.

Yes......but you have a brain.

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.

"Ed Huntress" wrote in message
.net...
BTW, if you find this entertaining, here's some newer data, based on
Doppler
radar research:

http://www.nennstiel-ruprecht.de/bullfly/anom.htm

Ed Huntress



This same web site that Ed quoted does have info on "falling bullets" at
http://www.nennstiel-ruprecht.de/bullfly/faq.htm#Q1 Third question from the
bottom. He does qualify his answer, but says that a military SS109 (whatever
that is) has a terminal velocity of 404 ft/sec. I wouldn't want to be hit by
that, would you?

Lane

Stan Schaefer wrote:



snipped



If you guys haven't caught Mythbusters, it's about debunking urban
myths. Some of the stuff that's shown so far has been about the guy
in the lawn chair and the weather balloons,

Did they claim *that* one was untrue?

My tuchstone of truth for such things has always been www.snopes.com. Here's what they say:

http://www.snopes.com/spoons/noose/balloon.htm

Now, what do *you* think Stan?

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."

"Dean" wrote in message
...
This is sort of metalwork - it involves lead. I was watching the Iraqies
celebrating the capture of Saddam by firing their rifles and guns into the
air. How dangerous are the bullets coming down ? I know they fall back
much
slower than they leave the gun barrel, but they must still be doing a fair
clip. They said 4 people so far have been killed by this but I guess in
Iraq
its hard to know which bullets came from where. As a few of you know about
guns I thought I'd ask here.

Dean.

( I notice they said Saddam was found in a rat infested hidey hole. I bet
the rats are glad he's moved out of the neighbourhood ! )



Anyone have access to this report?

Falling Bullets: Terminal Velocities and Penetration Studies - by Lucien C.
Haag
It is mentioned he http://home.sprynet.com/~frfrog/miscella.htm
and is available for order he http://www.iwba.com/backissue.htm

I don't have a spare $20 to spend on this right now.

It supposedly says: "As a point of interest a velocity of about between 160
and 200 f/s (±) is needed to penetrate skin."

Lane

I understand that the terminal velocity of a spread-eagled human is
something like 120 mph. It doesn't matter if you fall from 2,000 feet or
50,000 feet, you hit the ground at around 120 per. Does anyone have better
data on that?

Ed Huntress

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

In , on 12/15/03
at 06:57 AM, (J.R. Williams) said:

Tim:
Check "Hatcher's Notebook" and in the section on 'Bullets from the sky'
he records considerable data on experiments of vertical firing of ..30
cal 150 grain ammunition. With a muzzle velocity of 2700 ft/sec they
averaged only 300 ft/sec when they returned to the ground. This gives
an energy level of 30 ft. pounds and the Army considers 60 foot pounds to
produce a disabling wound. ("Hatcher's Notebook", Third edition,
pages 510 to 517). The majority of the bullets returned to earth base
first.

J.R. Williams

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?
-----------------------------------------------------------------------------------------------------
John Lloyd - Cymru/Wales

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In , on 12/15/03
at 06:19 PM, "Mike" said:

I would think a round lead ball would be the most dangerous.

How about a 16inch round from USS New jerseyGG

-----------------------------------------------------------------------------------------------------
John Lloyd - Cymru/Wales

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. 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.

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

In article , Jeff Wisnia says...

http://www.snopes.com/spoons/noose/balloon.htm

"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!

==================================================
please reply to:
JRR(zero) at yktvmv (dot) vnet (dot) ibm (dot) com
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Jeff Wisnia wrote in message ...
Stan Schaefer wrote:



snipped



If you guys haven't caught Mythbusters, it's about debunking urban
myths. Some of the stuff that's shown so far has been about the guy
in the lawn chair and the weather balloons,

Did they claim *that* one was untrue?

--
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."

No, they claimed that it was easily possible, and after their test, they
received copies of reports from various agencies documenting the original
flight.

Before their test, all they got was the runaround from the various agencies
they contacted trying to obtain information and permission for their test.

Paul K. Dickman

p.s. They also said it was possible to electrocute yourself by peeing on the
third rail, but that you would have to be kneeling in a puddle, and really
have to go.

"Erik" wrote in message
...

I understand that the terminal velocity of a spread-eagled human is
something like 120 mph. It doesn't matter if you fall from 2,000 feet or
50,000 feet, you hit the ground at around 120 per. Does anyone have
better
data on that?

Ed Huntress

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.)

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

wrote in message
ernet.com...

This was mentioned a few years back on the Compuserve Firearms Forum...

Hello, John. Weren't you there as far back as the early '90s?

Ed Huntress