Public service announcement for New Year's Eve

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ODA 226 wrote:

bigdaddy1 wrote:

The Mythbuster episode I described is on at this time (1:00 pm on Friday 01/01/10) on the Discovery channel

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Hey Brother.....You posted this at 2:14 pm. LOL!

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OK 1:14 p.m. central standard time

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bigdaddy1 wrote:

Mythbusters did a show about this a while back. If you can get your round to fire completely straight and true upward, it will loosemost of its energy on the way down. However it is nearly impossible to do this so there is an arch factor. The kinetic energy in the round in an arch is dangerous and can cause injuy.

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So did a "Thousand Ways to Die". The guy was leaving a New Years Eve party with his girlfriend and took a round to the chest that was fired from over a mile away.

Very few "celebratory" rounds are shot straight up into the air. Most are fired in "rapid" fire and are never precisely fired.

This type of fire is more than irresponsible...it is CRIMINAL!

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Master Doug Huffman wrote:

The conspiracy of ignorance masquerades as common sense.

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I don't need any citation for it, all I need is high school physics.

Ok, the acceleration due to gravity near the surface of the Earth is 9.8m/s squared.

That's about 32 ft/s squared.

If I stand next to you, and drop a bullet at the exact same time that you fire one out of a gun, into say an infinite open field, parallel to the gound,both bullets would hit the ground at the same time.

Why?

Gravity will pull on both rounds at exactly the same rate. The round in free fall will be falling at the exact same rate as the round fired by the gun. Horizontal speed has no effect, and cannot counteract the acceleration due to gravity. When the round that I dopped hits the ground, the round fired from the weapon will hit the ground at the same time. When mine hits the ground, yours has too.

Even if we started 5 meters off the ground, which is almost 16.5 feet off the ground, both rounds would hit the ground in one second. (That is half of the 9.8 m/s squared, since both object started at rest)

Also, a round fired either paralell to the ground, or at an upwards angle, will immediately start to lose speed due to air resistance, and this loss of speed will exponential as it travels and loses inertia.

I will simplify for you:

A 9mm round traveling at 300m/s (984 f/s) will only fly 165 meters (541 feet)before it hits the ground, if fired parallel to the ground. You could safely stand 600 feetdirectly in front of someonefiring the round, and it would not even reach you.

Now, increasing the fired angle will cause the projectile to go further, but it will be moving slower when it gets to it's target, due to deceleration from air resistance. The longer the round stays in the air, the longer it is in contact with the air causing the resistance, thus the slower it will be traveling when it arrives at it's final destination.

Now back to the whole firing into the air thing...

If you fire directly and straight into the air, the bullet will rise, stall, and then start to freefall. It cannot fall faster than it's terminal velocity, which is equivialant to the amount of air needed to stop it's acceleration, becuause it is not being propelled or acted upon by the explosive force of the gases that forced it down the barrel.This is also the amount of air it takes to START the object moving. Take a 9mm round, and place it on a table, and I bet you could blow hard enough to get it moving. That's with the added friction of the table it is sitting on, so imagine how little air it would take to cause that round to stop accelerating as it falls. Notice we are sayng make it stop accelerating, not make it stop it's motion altogether...



It's very similar to the old "Toss a penny off the Empire State Building" urban myth. While it may not be comfortable, and it may even hurt, the round cannon travel fast enough to seriously injure you coming straight back down on you.

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ODA 226 wrote:

bigdaddy1 wrote:

Mythbusters did a show about this a while back. If you can get your round to fire completely straight and true upward, it will loosemost of its energy on the way down. However it is nearly impossible to do this so there is an arch factor. The kinetic energy in the round in an arch is dangerous and can cause injuy.

Click to expand...

So did a "Thousand Ways to Die". The guy was leaving a New Years Eve party with his girlfriend and took a round to the chest that was fired from over a mile away.

Very few "celebratory" rounds are shot straight up into the air. Most are fired in "rapid" fire and are never precisely fired.

This type of fire is more than irresponsible...it is CRIMINAL!

Click to expand...

You realize that show is a crock, right? More than half the deaths they talk about are urban myths, or out right fabrications...
I think last night, they even had someone being killed by a meteorite, when there are only 2 recorded instances of people being struck by meteorites, and both persons survived with very minor injuries...

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superdemon wrote:

this loss of speed will exponential as it travels and loses inertia.

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Yes, proportional to V^2.

I think that you meant momentum, the product of velocity and mass, rather than inertia that is generally considered equal to mass.

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ODA 226 wrote:

HOLY MOLY! BIKENUT AND I ACTUALLY AGREE ON SOMETHING!

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More often than you are aware my 'net friend.

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superdemon wrote:

I don't need any citation for it, all I need is high school physics.

Ok, the acceleration due to gravity near the surface of the Earth is 9.8m/s squared.

That's about 32 ft/s squared.

If I stand next to you, and drop a bullet at the exact same time that you fire one out of a gun, into say an infinite open field, parallel to the gound,both bullets would hit the ground at the same time.

Why?

Gravity will pull on both rounds at exactly the same rate. The round in free fall will be falling at the exact same rate as the round fired by the gun. Horizontal speed has no effect, and cannot counteract the acceleration due to gravity. When the round that I dopped hits the ground, the round fired from the weapon will hit the ground at the same time. When mine hits the ground, yours has too.

Even if we started 5 meters off the ground, which is almost 16.5 feet off the ground, both rounds would hit the ground in one second. (That is half of the 9.8 m/s squared, since both object started at rest)

Also, a round fired either paralell to the ground, or at an upwards angle, will immediately start to lose speed due to air resistance, and this loss of speed will exponential as it travels and loses inertia.

I will simplify for you:

A 9mm round traveling at 300m/s (984 f/s) will only fly 165 meters (541 feet)before it hits the ground, if fired parallel to the ground. You could safely stand 600 feetdirectly in front of someonefiring the round, and it would not even reach you.

Now, increasing the fired angle will cause the projectile to go further, but it will be moving slower when it gets to it's target, due to deceleration from air resistance. The longer the round stays in the air, the longer it is in contact with the air causing the resistance, thus the slower it will be traveling when it arrives at it's final destination.

Now back to the whole firing into the air thing...

If you fire directly and straight into the air, the bullet will rise, stall, and then start to freefall. It cannot fall faster than it's terminal velocity, which is equivialant to the amount of air needed to stop it's acceleration, becuause it is not being propelled or acted upon by the explosive force of the gases that forced it down the barrel.This is also the amount of air it takes to START the object moving. Take a 9mm round, and place it on a table, and I bet you could blow hard enough to get it moving. That's with the added friction of the table it is sitting on, so imagine how little air it would take to cause that round to stop accelerating as it falls. Notice we are sayng make it stop accelerating, not make it stop it's motion altogether...



It's very similar to the old "Toss a penny off the Empire State Building" urban myth. While it may not be comfortable, and it may even hurt, the round cannon travel fast enough to seriously injure you coming straight back down on you.

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The part in blue is misleading... because at 541 feet (180 + a little yards) that 9mm bullet still has quite a bit of velocity/momentum and there is no guarantee that round will stop when it impacts the earth... it might just skip off the ground and keep on going for a good little while.

Because bullets have a tendency to skip off of flat ground standing in the line of fire at 600 feet (200 yards) wouldn't be a good idea.

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superdemon wrote:

ODA 226 wrote:

bigdaddy1 wrote:

Mythbusters did a show about this a while back. If you can get your round to fire completely straight and true upward, it will loosemost of its energy on the way down. However it is nearly impossible to do this so there is an arch factor. The kinetic energy in the round in an arch is dangerous and can cause injuy.

Click to expand...

So did a "Thousand Ways to Die". The guy was leaving a New Years Eve party with his girlfriend and took a round to the chest that was fired from over a mile away.

Very few "celebratory" rounds are shot straight up into the air. Most are fired in "rapid" fire and are never precisely fired.

This type of fire is more than irresponsible...it is CRIMINAL!

Click to expand...

You realize that show is a crock, right? More than half the deaths they talk about are urban myths, or out right fabrications...
I think last night, they even had someone being killed by a meteorite, when there are only 2 recorded instances of people being struck by meteorites, and both persons survived with very minor injuries...

Click to expand...

Then how do you explain my friend that was shot in the head by an AK round and partially paralized while standing in the main square of Zagreb on New Years Eve 1996? I can provide instances of celebratory fire DEATHS if you give me a few days.

This behavior is CRIMINAL!

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I stood outside on the front porch at Midnight for a couple of minutes to listen to the soundsone normally hears on theFourth of July. I couldn't tell if it was gunfire or firecrackers--probably both. Went back inside just to be safe. I have a tendency to lean towards caution...

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Part of the Myth Busters show discussed that if the bullet loses its spin/rifling and tumbles it becomes much less dangerous. Terminal velocity and all reduce the danger but it is still dangerous "best case" and deadly worst case.

Where it hits is the problem. If it hits a child in the head its over. If it hits you in the jugular its over. How about your eye? They tested to see if it would penetrate an adult cranium at terminal velocity if it was tumbling. We already know it will if it isn't being limited by terminal velocity.

The show also documents a few cases of people hit by celebratory bullets and dying. I beleive in those cases the bullet never lost its arc and spin so it never tumbled.

So morale of the story, "Don't be an asshat!"

Edited to add: I remember recently a child/infant hit by a bullet in a church service. The bullet came down through the roof and into the childs leg. The mother thought the child was just being fussy and found the bullet/wound when she took the child out and checked its diaper. Imagine if that hit the childs head instead of its leg.

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All of those that promoting themselves as physics experts should volunteer for a demonstration and catch the falling bullets.

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buster81 wrote:

All of those that promoting themselves as physics experts should volunteer for a demonstration and catch the falling bullets.

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:lol:There ya go... No thanks!

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hopnpop wrote:

buster81 wrote:

All of those that promoting themselves as physics experts should volunteer for a demonstration and catch the falling bullets.

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:lol:There ya go... No thanks!

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HAHAHA! LMAO! :celebrate

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...thinking that when skydiving, term velocity, depending on your gear and position, is ballparked at around 120mph. I certainly wouldn't even want to get hit with 115grs of lead travelling at that speed (especially to the noggin).

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It's too bad that the ignorant conspirators, suggesting that another be the first to catch a falling bullet, can't be the first to dive the sky.

We stand on the shoulders of giants.

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hopnpop wrote:

...thinking that when skydiving, term velocity, depending on your gear and position, is ballparked at around 120mph. I certainly wouldn't even want to get hit with 115grs of lead travelling at that speed (especially to the noggin).

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But like I said, it would not travel nearly120 mph.

Terminal velocity is reached when the falling body is being pushed up against by air resistance equal to it's mass. A human falling has much more mass than a falling round, therefore, the human will have a higher teminal velocity than the round. And yes, I would be perfectly willing to attempt to catch a round FALLING at terminal velocity. It would have no more speed/impact than a granite rock of the same/similar mass falling from the same height.

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Master Doug Huffman wrote:

superdemon wrote:

this loss of speed will exponential as it travels and loses inertia.

Click to expand...

Yes, proportional to V^2.

I think that you meant momentum, the product of velocity and mass, rather than inertia that is generally considered equal to mass.

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Yes, thank you for the correction. I was heavily medicated for my sinus infection when I wrote my response.

Inertia is constant, as long as the mass is constant.

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buster81 wrote:

All of those that promoting themselves as physics experts should volunteer for a demonstration and catch the falling bullets.

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Again, I never said I was a physics expert. I said it was using high school physics.

That certainly does not make me an expert in physics. I'm no more an expert in physics than I am in chemistry, history, English, etc.

I can't help it if you didn't pay attention in high school.

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superdemon wrote:

Terminal velocity is reached when the falling body is being pushed up against by air resistance equal to it's mass.... It would have no more speed/impact than a granite rock of the same/similar mass falling from the same height.

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For inexpert, you're doing fine.

Terminal velocity is reached when the falling body is being resisted, "pushed up against", by an air resistance equal to its normal force weight. Again, the air resistance drag force is proportional to V^2.

The rock would need a similar shape. I think that the largest component of drag is the projected 'frontal' area.

If you're an expert then you must be an elite and therefore disbelieved by the hoi polloi.