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Bullets falling back to earth
I've been around celebrations in the Balkans and Mexico where they were
firing guns into the air. Two things I noticed were that they were almost always above 45 degrees and they were usually pointed towards some uninhabited mountain or out to sea. Most of the cultures that fire guns into the air are fairly gun savvy. |
Bullets falling back to earth
On Mon, 15 Dec 2003 16:57:26 +0000, Andy Dingley
wrote: It is possible to go supersonic in free-fall Space shuttle is the best example of that. And it isn't going anywhere near straight down. Dave |
Bullets falling back to earth
On Mon, 15 Dec 2003 11:11:04 -0600, the renowned David A. Webb
wrote: On Mon, 15 Dec 2003 16:57:26 +0000, Andy Dingley wrote: It is possible to go supersonic in free-fall Space shuttle is the best example of that. And it isn't going anywhere near straight down. The space shuttle in LEO is over 17,000 MPH; it has to slow down A LOT to just be going supersonic. 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 |
Bullets falling back to earth
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. Ted |
Bullets falling back to earth
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. I think on earth too. The downward component of the areodynamic (sic) drag will be the same in both cases. Now if you got some spin on the fired cannon ball, things might be different. |
Bullets falling back to earth
"Ted Edwards" wrote in message ... 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. Ted I believe it to be so on earth, aerodynamic drag will act upon the bullet's horizontal motion, gravity will act upon it's vertical drop. think about it a little more and you might agree. JTMcC. |
Bullets falling back to earth
"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. ================================================== please reply to: JRR(zero) at yktvmv (dot) vnet (dot) ibm (dot) com ================================================== |
Bullets falling back to earth
In article ,
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. Ted Even on earth. Basic physics has us break things up into components. A cannon ball fired exactly horizontal will have tremendous velocity horizontally, and none vertically. While the horizontal velocity will be decreasing due to friction with the air, the vertical velocity will be increasing due to gravity. This increase works just the same as if you dropped the bowling ball. So a bowling ball dropped from the same height as the muzzle of the cannon will reach the ground in the exact same time as the cannon ball that was fired from the cannon (neglecting curvature of the earth and other such factors such as spin on the ball producing lift, etc.). Since both cannon balls are the same size and mass and have the same initial conditions in the vertical direction, they are for all intents and purposes identical in behavior on the vertical axis. Horizontal is obviously a different ball of wax. -- Joe -- Joseph M. Krzeszewski Mechanical Engineering and stuff Jack of All Trades, Master of None... Yet |
Bullets falling back to earth
On Mon, 15 Dec 2003 11:11:04 -0600, David A. Webb
wrote: On Mon, 15 Dec 2003 16:57:26 +0000, Andy Dingley wrote: It is possible to go supersonic in free-fall Space shuttle is the best example of that. And it isn't going anywhere near straight down. Dave Wouldnt the Shuttle have started out way up up beyond Mach 50, and slows down as it enters atmosphere, ultimately falling below supersonic as it finds its terminal velocity? Its actually slowing, rather than speeding up as it falls. The Mach 50 G figure being sheer hyperbole as there is no speed of sound in orbit. 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 |
Bullets falling back to earth
On Mon, 15 Dec 2003 09:00:14 -0800, Jim McGill
wrote: I've been around celebrations in the Balkans and Mexico where they were firing guns into the air. Two things I noticed were that they were almost always above 45 degrees and they were usually pointed towards some uninhabited mountain or out to sea. Most of the cultures that fire guns into the air are fairly gun savvy. Seems they have an edge over East L.A. 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 |
Bullets falling back to earth
A 30.06 rifle bullet has a muzzle velocity almost 3000 ft. per second.
This equates to approx.2045.5 mph. a bullet falling straight back to earth has the law of gravity pulling it and with wind resistance will attain a velocity of approx. 150 mph. which equates to about 102 ft per second. about the weakest firearm cartridge there is a .25 cal and it's muzzle velocity is over 500 ft. per second which is five times the speed of a falling bullet and a .25 cal. is so weak that very often when someone is shot with one all it does is get them mad where as they take the gun away and wip your ass. -- Building and repair of fine custom cues at affordable prices for real poolplayers. Over 35yrs. exp. Richard H. Neighbors 318 Linden st. Cinti. OH ph.# (513) 242-1700 web-site: http://www.dickiecues.com "JTMcC" wrote in message ... "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 |
Bullets falling back to earth
On Mon, 15 Dec 2003 11:11:04 -0600, David A. Webb
wrote: On Mon, 15 Dec 2003 16:57:26 +0000, Andy Dingley wrote: It is possible to go supersonic in free-fall Space shuttle is the best example of that. Sorry, it's a very poor example - nearly as poor as my wording in the previous comment. I should have said "reached terminal velocity in free fall", with the emphasis on "reaching". The shuttle is fast when it arrives, and getting slower all the way down. If you dropped a stationary shuttle from altitude, it certainly wouldn't _go_ supersonic. |
Bullets falling back to earth
According to a book entitled "Hatcher's Notebook", the US Army performed tests
in Florida swamps in the first half of the 20th century by firing a 30 cal. machine gun straight up into the air and carefully evaluating the returning bullets. They determined that the returning 30 cal. 150 grain bullet would reach a maximum terminal velocity less than that required to penetrate the skull of an adult male, or reliably cause a disabling wound. The terminal velocity was limited by the air resistance acting on the bullet as it fell, thus limiting its impact energy. However a falling 50 cal bullet, due to its greater mass, was considered a lethal threat. Don't try this at home! If you want more details, the book is interesting reading. JM |
Bullets falling back to earth
In article , Gunner says...
The Mach 50 G figure being sheer hyperbole as there is no speed of sound in orbit. Well there has to be. How else could stuff go "boom" in space, in all those movies? LOL Jim ================================================== please reply to: JRR(zero) at yktvmv (dot) vnet (dot) ibm (dot) com ================================================== |
Bullets falling back to earth
On Mon, 15 Dec 2003 15:37:03 GMT, "Bob Swinney" wrote:
It is unclear if the accounts given below involve bullets falling only under the influence of gravity - that is straight down. It is far more likely they involve "stray" bullets that retain some component of forward velocity imparted by the firing charge. Gunner's comments, elsewhere in this post, make it clear that "service size" projectiles falling only under the force of gravity are not likely to inflict mortal wounds. Kinetic energy = 1/2 mv*2 In the case of a 150 grain bullet falling at 300 fps, its kinetic energy is: Ke = 0.5 x (150/7000)/32) x 300*2 = ~30 ft. lbs. Bullet weight in grains divided by 7000 = weight in lbs. Weight divided by 32 = poundals or mass associated with gravity. Bob Swinney 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. Mark Rand RTFM |
Bullets falling back to earth
In article ,
"rhncue" wrote: A 30.06 rifle bullet has a muzzle velocity almost 3000 ft. per second. This equates to approx.2045.5 mph. a bullet falling straight back to earth has the law of gravity pulling it and with wind resistance will attain a velocity of approx. 150 mph. which equates to about 102 ft per second. about the weakest firearm cartridge there is a .25 cal and it's muzzle velocity is over 500 ft. per second which is five times the speed of a falling bullet and a .25 cal. is so weak that very often when someone is shot with one all it does is get them mad where as they take the gun away and wip your ass. -- Building and repair of fine custom cues at affordable prices for real poolplayers. Over 35yrs. exp. Richard H. Neighbors 318 Linden st. Cinti. OH ph.# (513) 242-1700 web-site: http://www.dickiecues.com 150 mph is about 220 ft/s, not 102. (1 mph is about 1.467 ft/s)... If the .25 cal goes 500 ft/s, thats around 341 mph... have you ever been close to something going that fast? I have... and I'm sure wouldn't want to be hit by anything going that fast. Back in the old skydiving days, a guy still in freefall grazed the skirt of an open canopy with his hand & lower arm. He probably had a closing speed of about 110 mph (only a measly 161.3 ft/s). Thats 120 mph terminal freefall speed minus the roughly 10 mph decent speed of the open round canopy. Neither he, or the other two witnesses thought any part of the canopy or lines had wrapped around him in any way... but wow, what mess it made of him... multiple compound fractures, and all the fun associated stuff that goes with them. I think if I were shot with a .25, and ended up only being mad, I'd be VERY lucky. Erik |
Bullets falling back to earth
Andy Dingley wrote:
... It is possible to go supersonic in free-fall - the WW2 Grand Slam bomb ... Actually, there was a man that went supersonic in free fall! IIRC, it was post W.W.II and the Air Force sent an officer up in a balloon. _Really_ up, like altitude record high. He jumped out and did free fall for a _long_ time. Since he was so high, the speed of sound was considerably less than at sea level (air density thing) and he actually exceeded it. Or so I heard on the Discovery channel, or TLC - one of them. Bob |
Bullets falling back to earth
I would think a round lead ball would be the most dangerous. No tumbling
to cut down on drag and quick terminal velocity. An ounce lead ball shot skyward with a good sling shot might reach terminal velocity on the way down and I sure wouldn't won't to be on the receiving end of it. |
Bullets falling back to earth
"Tim Williams" wrote in message ...
"Chris Oates" none wrote in message ... Yes, same velocity they went up with Nope. As soon as it leaves the barrel it's slowing down, as, AFAIK, bullets are supersonic, and I know of nothing that has a terminal speed greater than the speed of sound, at least at this size! After it reaches the apex, where its vertical speed is zero, it is now speeding up, and will slowly (exponential decay style) approach terminal speed. Donno what number that is, though. Tim 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 |
Bullets falling back to earth
Sounds like another story I heard:
An Air Force pilot was trying to fly his fighter through a major thunderstorm, when his engine gave out near the middle of the thing. He bailed out, and because he was caught in the up draft, spent close to an hour in the air without his plane. By the time he finally landed, his uniform was shredded, and he was black and blue from head to foot. Greg H. "Bob Engelhardt" wrote in message ... Andy Dingley wrote: ... It is possible to go supersonic in free-fall - the WW2 Grand Slam bomb ... Actually, there was a man that went supersonic in free fall! IIRC, it was post W.W.II and the Air Force sent an officer up in a balloon. _Really_ up, like altitude record high. He jumped out and did free fall for a _long_ time. Since he was so high, the speed of sound was considerably less than at sea level (air density thing) and he actually exceeded it. Or so I heard on the Discovery channel, or TLC - one of them. Bob |
Bullets falling back to earth
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 "Mark Rand" wrote in message ... On Mon, 15 Dec 2003 15:37:03 GMT, "Bob Swinney" wrote: It is unclear if the accounts given below involve bullets falling only under the influence of gravity - that is straight down. It is far more likely they involve "stray" bullets that retain some component of forward velocity imparted by the firing charge. Gunner's comments, elsewhere in this post, make it clear that "service size" projectiles falling only under the force of gravity are not likely to inflict mortal wounds. Kinetic energy = 1/2 mv*2 In the case of a 150 grain bullet falling at 300 fps, its kinetic energy is: Ke = 0.5 x (150/7000)/32) x 300*2 = ~30 ft. lbs. Bullet weight in grains divided by 7000 = weight in lbs. Weight divided by 32 = poundals or mass associated with gravity. Bob Swinney Mark Rand RTFM |
Bullets falling back to earth
"Erik" wrote in message ... In article , "rhncue" wrote: A 30.06 rifle bullet has a muzzle velocity almost 3000 ft. per second. This equates to approx.2045.5 mph. a bullet falling straight back to earth has the law of gravity pulling it and with wind resistance will attain a velocity of approx. 150 mph. which equates to about 102 ft per second. about the weakest firearm cartridge there is a .25 cal and it's muzzle velocity is over 500 ft. per second which is five times the speed of a falling bullet and a .25 cal. is so weak that very often when someone is shot with one all it does is get them mad where as they take the gun away and wip your ass. -- Building and repair of fine custom cues at affordable prices for real poolplayers. Over 35yrs. exp. Richard H. Neighbors 318 Linden st. Cinti. OH ph.# (513) 242-1700 web-site: http://www.dickiecues.com 150 mph is about 220 ft/s, not 102. (1 mph is about 1.467 ft/s)... If the .25 cal goes 500 ft/s, thats around 341 mph... have you ever been close to something going that fast? I have... and I'm sure wouldn't want to be hit by anything going that fast. An aquantance of mine, who did business with my brother, emptied a .25 into a fleeing felon's back with little or no effect (I know, that's normally considered a no no), and ended up killing the man by knocking him down and kicking him in the head. My brother, a gun dealer, had tried to convince the guy to buy a major caliber pistol. He was tried and aquitted by jury. And now owns a .40 JTMcC, happily carrying a .45acp for many years now. Back in the old skydiving days, a guy still in freefall grazed the skirt of an open canopy with his hand & lower arm. He probably had a closing speed of about 110 mph (only a measly 161.3 ft/s). Thats 120 mph terminal freefall speed minus the roughly 10 mph decent speed of the open round canopy. Neither he, or the other two witnesses thought any part of the canopy or lines had wrapped around him in any way... but wow, what mess it made of him... multiple compound fractures, and all the fun associated stuff that goes with them. I think if I were shot with a .25, and ended up only being mad, I'd be VERY lucky. Erik |
Bullets falling back to earth
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. |
Bullets falling back to earth
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 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 |
Bullets falling back to earth
"ATP" wrote in message .net... 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. 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. |
Bullets falling back to earth
"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 |
Pennies thrown from Empire State Building was Bullets falling back to earth
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. |
Bullets falling back to earth
We aren't living in a vacume around here. I believe you are misstaken when
you say a "little" slower. Nah! It is a lot slower - physics 101 stuff indeed. Bob Swinney "JTMcC" wrote in message ... "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 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 |
Bullets falling back to earth
On Tue, 16 Dec 2003 03:10:12 GMT, "JTMcC"
wrote: "ATP" wrote in message v.net... 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. 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. The only difference is the 4000fps bullet will go higher than the 2800 fps bullet. This will only affect the downward speed of the bullet if the max elevation is not high enough to allow the falling bullet to reach terminal velocity. The accelleration of gravity is sufficient to make a 22 caliber projectile reach terminal velocity in significantly less than the verticle distance covered by even a 2700fps projectile, I am sure. |
Bullets falling back to earth
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. 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. -- Email: | Voice (all times): (703) 938-4564 (too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html --- Black Holes are where God is dividing by zero --- |
Bullets falling back to earth
"J.R. Williams" wrote: "Tim Williams" wrote in message ... "Chris Oates" none wrote in message ... Yes, same velocity they went up with Nope. As soon as it leaves the barrel it's slowing down, as, AFAIK, bullets are supersonic, and I know of nothing that has a terminal speed greater than the speed of sound, at least at this size! After it reaches the apex, where its vertical speed is zero, it is now speeding up, and will slowly (exponential decay style) approach terminal speed. Donno what number that is, though. Tim 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 It is from Hatcher's book that I got the 300 fps data. And contrary to all the nonsense and no fact statements here made by many, Hatcher's groups did find that bullets fired straight up did not routinely turn over but came down base first as you said; some however tumbled or came down pointy end first. Regardless of all the nonsense stated by some here, 300 fps is pretty slow moving in the field of weapons. BBs, air pellets, sling shots, arrows, etc. can be higher than 300 fps, and all except BBs and pellets are likely much larger and to weigh more than 150 grains. A tiny thing weighing only 150 grains isn't going to do much compared to something weighing a pound. The comparison has to be made considering both speed and weight. |
Bullets falling back to earth
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Bullets falling back to earth
Dan Thomas wrote: "Tim Williams" wrote in message ... "Chris Oates" none wrote in message ... Yes, same velocity they went up with Nope. As soon as it leaves the barrel it's slowing down, as, AFAIK, bullets are supersonic, and I know of nothing that has a terminal speed greater than the speed of sound, at least at this size! After it reaches the apex, where its vertical speed is zero, it is now speeding up, and will slowly (exponential decay style) approach terminal speed. Donno what number that is, though. Tim 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. |
Bullets falling back to earth
On Tue, 16 Dec 2003 03:33:06 GMT, bart wrote:
kinda OT.. I remember as a kid, the army surplus store had crates of little ( 1-2oz?) lead teardrop shaped things with little tin fins ( bomb shape) & the guy told me they were designed to be dropped from planes.. Most of those were actually steel. The name escapes me..something Dog..but they were used as antipersonel devices against factories and such. Kick out several tons of those killer bees over a manned factory..and they would wreck havoc both on the machinery and the personel. Very aerodynamic, hardened steel IRRC... terminal ballistics quite high and the kinetic energy was very potent with that much drop weight. The modern cluster bomb has its roots in these bomblets 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 |
Bullets falling back to earth
In article ,
Gunner wrote: On Tue, 16 Dec 2003 03:33:06 GMT, bart wrote: kinda OT.. I remember as a kid, the army surplus store had crates of little ( 1-2oz?) lead teardrop shaped things with little tin fins ( bomb shape) & the guy told me they were designed to be dropped from planes.. Most of those were actually steel. The name escapes me..something Dog..but they were used as antipersonel devices against factories and such. Kick out several tons of those killer bees over a manned factory..and they would wreck havoc both on the machinery and the personel. Very aerodynamic, hardened steel IRRC... terminal ballistics quite high and the kinetic energy was very potent with that much drop weight. The modern cluster bomb has its roots in these bomblets Reminds me of those toy 'Lawn Dart' things? I think a few people were hurt & killed by them before they were pulled off the market. Erik |
Bullets falling back to earth
"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 |
Bullets falling back to earth
On Mon, 15 Dec 2003 09:03:45 +0800, "Dean"
wrote: 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 ? Other posts may have said this, , please pardon my not wading thru them all. A bullet fired at a high angle will reach whatever altitude it reaches, at which point it will be become a vertically-stationary object. Events thenceforth are no different than dropping said object from that height. It will then fall, accelerated by gravity until its weight equals aerodynamic drag. That speed is terminal velocity that depends entirely on shape and weight, not at all on initial muzzle velocity. Think lead raindrops. Cannon balls fall faster than bird shot regardless of muzzle velocity that put them at altitude. A falling 7.62mm or 30.06 bullet would dent your helmet but probably not punch it, a falling 155 mm dud round surely would. |
Bullets falling back to earth
I was told that they were called Crazy Dogs.
The ones I saw at gun shows were made of hard lead with sheet metal fins. I think that the original cluster bombs were bunches of small anti personal ' butterfly ' bombs packed in a canister, and dropped by the Germans in WW2. Greg H. "Gunner" wrote in message ... On Tue, 16 Dec 2003 03:33:06 GMT, bart wrote: Most of those were actually steel. The name escapes me..something Dog..but they were used as antipersonel devices against factories and such. Kick out several tons of those killer bees over a manned factory..and they would wreck havoc both on the machinery and the personel. Very aerodynamic, hardened steel IRRC... terminal ballistics quite high and the kinetic energy was very potent with that much drop weight. The modern cluster bomb has its roots in these bomblets |
Bullets falling back to earth
On Tue, 16 Dec 2003 06:15:26 GMT, Erik wrote:
In article , Gunner wrote: On Tue, 16 Dec 2003 03:33:06 GMT, bart wrote: kinda OT.. I remember as a kid, the army surplus store had crates of little ( 1-2oz?) lead teardrop shaped things with little tin fins ( bomb shape) & the guy told me they were designed to be dropped from planes.. Most of those were actually steel. The name escapes me..something Dog..but they were used as antipersonel devices against factories and such. Kick out several tons of those killer bees over a manned factory..and they would wreck havoc both on the machinery and the personel. Very aerodynamic, hardened steel IRRC... terminal ballistics quite high and the kinetic energy was very potent with that much drop weight. The modern cluster bomb has its roots in these bomblets Reminds me of those toy 'Lawn Dart' things? I think a few people were hurt & killed by them before they were pulled off the market. Erik Which brings to mind a story about a party, the neighbors Pekinese (sp?) a tall fence and a miss thrown lawn dart. Not for the squeemish. 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 |
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