Just watching the news about Saddam and the folks in Iraq firing their guns in the air and wondered how far the bullits would travel assuming they don't hit anything!

I guess if you were unlucky enough to be at the point that it drops out of the sky it would still hurt, alot...

Maybe it's one for the muppet show?

Darren

 

Fortuantely air resistance means the bullet won't come down at the same speed it went up, but having had spent SSG size shot (buckshot) land on me yes it does still sting!

[Edited by ajm - 12/14/2003 12:07:41 PM]

 

You can be killed by a bullet returning to earth, perhaps not the best way to celebrate ?

 

taken for another website:

"Bullets fired into the air can climb as high as two miles before plummeting to the earth at speeds of 300 to 500 feet per second. A speed of 200 feet per second is sufficient to break bone and penetrate the skull, according to a 1995 study by Martin Luther King/Drew Medical Center."

 

Given that most of the weapons seem to AK47 style, the bullets are most likely 7.62mm which is a fairly sizeable bullet to come hurtling back down to earth. I wonder how many fatalities with wounds to the top of the head have been blamed on allied forces?!

 

Frightening how many of them actually have guns in the first place.

 

I suppose the reason why we don't see people in these crowds dropping down dead from the impact of "returning" rounds is that it is highly unlikely that the round was fired perpendicular to the ground and even a small angle would be sufficient to ensure that the round lands some considerable distance displaced from the point of launch. It is probably reasonable to assume that the density of people in the area where the round falls is going to be less than in the area from which it was launched and so it's chances of hitting someone are greatly reduced.

I know that this is a topic which has been subject to some considerable discussion in books on the matter. However, I have never seen a definitive conclusion and I suppose when you take wind etc. into consideration it is going to be hard to produce a "one size fits all" answer. One thing I did see concluded was that a round sent straight up would fall back down tail first due to the considerable rate of spin imparted by the barrel. A bullet will spin about 250,000 rpm and in the time taken for the round trip this is not reduced sufficiently to render it unstable.

Far from being a muppet show question I suspect this is a very tricky one indeed.

 

I thought about this the other day, whilst watching the Rock, as a couple of squaddies fired their guns at approx 40-45 degree angle at a funeral (gun salute thingy)

What would happen to the bullet when fired like this (assuming it didnt hit a tree/building etc)

edited to add

I assume it would eventually lose velocity and fall down to the ground, and more likely to cause much less of a sting than if fired straight up in the air


[Edited by *Sonic* - 12/14/2003 3:40:01 PM]

 

At a funeral they would use blanks!

However, assuming no air resistance, 45 degrees is the optimum angle to launch a projectile for maximum range.

But to answer your question, if they were live rounds, the round would continue to fly until it hit the ground or someone/thing, albeit at a lower velocity than when it left the barrel! The bullet will always have some horizontal velocity left when it hits the ground, unless it was fired upwards at 90 degrees.

[Edited by ajm - 12/14/2003 3:49:41 PM]

 

Gun Salutes use blank rounds

 

DOH !

Why didnt I think of that

Cheers

 

Here's one for ya. If you hold a gun in your hand and fire it exactly horizontally and drop the gun at the moment it fires, the gun will hit the ground the same time that the bullet does .......

 

 

Precisely right! It makes no difference that the bullet is moving forward, gravity still acts on it in exactly the same way it would the gun when you drop it, hence both accelerate downwards at 9.81 metres per second per second and touch the ground at the same time!

 

Has anyone seen the film 'The Mexican'? I'm pretty sure some dude gets killed by the method described above.

Apparently, if you drop a coin from the top of the Empire State building it gathers enough velocity to kill someone on the sidewalk below! Or was it a sandwich? A grand piano would definitely do it..

 

Grand piano jamie ...haha ....made me chuckle

Play up pompey

 

Would be the case if on the moon or in a vacuume.

 

Yes there is still gravity on the moon it's just not as strong, so they would still hit the ground at the same time but it would just take about 9 times longer! Or maybe the bullet would stay still and the gun would go flying backwards??! As for a vacuum not sure, I don't know if a vacuum would have any effect on gravity?

 

Pompey play up

(We're just not very good at taking corners)

 

I'm afraid, my good fellow, you've misinterpreted my post. I was hinting at the possible effects of air resistance/friction, for you see neither the moon nor a vacuum has any air present. The curvature of the earth would all result in the fired bullet dropping fractions of a second after the gun.

 

But I thought the earth was flat!!

 

Would the bullet not fire quicker in a vacuum because there is a greater pressure between the barrel behind the bullet and the outside?

 

Read somewhere that if you can have a pole 1 mile long suspeded in a perfectly horizontal plane at the middle at sea level, the two ends will be about 4 inches above water due to curvature of the earth. So if the bullet has a range of say 1/2 mile, the bullet will hit earth later than the gun by the time taken to fall a further 4 inches under 1 g acceleration.

 

Gravity always acts towards the centre of the earth so the curvature of the earth would make negligable difference.

Practically speaking I think we can take the liberty of neglecting air resistance for this rather rudimentary example!

 

a bullit will travel for thousands of miles ............













































if it's in a plane

 

A bullet fired in a vacuum at 45Deg will travel around 20 times further than one fired in air. So air resistance does play a major part, even in our rudimentary example!

Also, if you could fire a round at five miles p/sec it would never touch down.

 

Yes, but we were talking about how quick the bullet fired horizontally hits the ground compared to the gun. This has nothing to do with horizontal distance.

The time difference, due to air resistance, between the bullet and the gun, both being dropped from about 5 feet above ground level (about where you would fire a gun), is negligable!

 

but would a bullet fire in a vacuum? surely oxygen will be required for the explosion?

 

The ordnance filler has various oxides in it.

 

If you could fire a bullet fast enough, would it travel all the way around the world and hit the back of the gun? (assuming it wasn't dropped)
















BTW