when you shoot a gun aimed upward at the sky...

[KingNothing]

Originally posted by: gopunk

Originally posted by: rbloedow

Originally posted by: gopunk
wouldn't that be dangerous? it goes up with a starting velocity, so presumably it would come down with something close to that velocity?

No, all things fall at the same rate, once gravity is pulling the bullet down, it falls at a steady rate. This fallacy is also the logic behind the myth of throwing a penny off of the empire state building and it killing the person who's head it lands on.

argh you people are pissing me off. you're misunderstanding my question, i've taken freshman physics! see above post

Your question has been answered by many people. The object will hit the ground at the same speed as if it were dropped from its peak height. The force it hits the ground with will be determined by its mass. Acceleration is a constant, unless the object is shaped in such a way as to fall oddly (like a leaf).

 

[gopunk]

Originally posted by: rbloedow

Originally posted by: gopunk

Originally posted by: rbloedow

Originally posted by: gopunk wouldn't that be dangerous? it goes up with a starting velocity, so presumably it would come down with something close to that velocity?

No, all things fall at the same rate, once gravity is pulling the bullet down, it falls at a steady rate. This fallacy is also the logic behind the myth of throwing a penny off of the empire state building and it killing the person who's head it lands on.

argh you people are pissing me off. you're misunderstanding my question, i've taken freshman physics! see above post

Maybe you misunderstood your own question in your head and then formulated it into a sentence incorrectly.

where in my post did i imply that i was not aware that all falling objects have g acceleration?

 

[glugglug]

Objects that small have terminal velocity pretty low. Air resistance will keep it from reaching high speed due to small mass to surface area ratio. My guess on the speed it reaches would be somewhere around 20-30MPH. Might leave somebody a bruise or a bump on the head but wouldn't come down fast enough to embed into someone.

This principle works with small animals too. You can drop a mouse or hamster off the empire state building and the speed they reach in freefall is low enough they can walk away unscathed.

A slightly larger animal like a house cat would probably break some bones but the fall would likely not be fatal, unless the cat looks like this one

If the bullet came down fast enough to kill can you imagine how many people would die in hailstorms?

 

[Brutuskend]

Things that make you go hmm....

rh71 hasn't killed his dumb self yet. Humm

 

[gopunk]

Originally posted by: KingNothing

Originally posted by: gopunk

Originally posted by: rbloedow

Originally posted by: gopunk
wouldn't that be dangerous? it goes up with a starting velocity, so presumably it would come down with something close to that velocity?

No, all things fall at the same rate, once gravity is pulling the bullet down, it falls at a steady rate. This fallacy is also the logic behind the myth of throwing a penny off of the empire state building and it killing the person who's head it lands on.

argh you people are pissing me off. you're misunderstanding my question, i've taken freshman physics! see above post

Your question has been answered by many people. The object will hit the ground at the same speed as if it were dropped from its peak height. The force it hits the ground with will be determined by its mass. Acceleration is a constant, unless the object is shaped in such a way as to fall oddly (like a leaf).

think about it. it is fired with initial velocity such that it reaches a certain height (slowed down by g). doesn't it make sense then, that the velocity gravity would have added by the time it hit earth again would be similar to the initial velocity? of course this is all without air resistance... but you guys are talking about something completely different...

 

[KingNothing]

Originally posted by: rh71
Ok, I thought it was obvious that I was looking for answers aside from the OBVIOUS of "it comes back down" ...

9.8 meters/second^2 = acceleration due to gravity...

Fine... this would kill someone, no ? Have you ever thought about it ?Your standard handgun (whatever that may be) ... how much altitude do you think a bullet will have gained before it comes back down? 5k feet? 20k feet?

Not looking for scientific answers, just your thoughts...

So...you don't want to know what the real answer is? Fine.

I think the bullet would actually have more force on the way down because of all the potential energy it would build up during its ascent, which would add to all the energy it would build up going down. I also think the heat generated by this process (you know how the space shuttle gets real hot on reentry? same thing) would cause the tip to fracture. This would cause the bullet to fragment when it hit the person on the ground, causing massive internal damage. This is why the army invented mortars, because they hit the ground with more force than if they were shot straight at their target.

 

[Looney]

Originally posted by: glugglug


This principle works with small animals too. You can drop a mouse or hamster off the empire state building and the speed they reach in freefall is low enough they can walk away unscathed.

Hmmmm are you serious? I think we'll need to seriously test this. My friend lives on the 18th floor, i'll try it this weekend with his hamster.

 

[crab]

THIS can happen...

I met Joe during my "stay" at A. I. Dupont hospital in Delaware...He'll never be the same as he was before that night.

 

[WinkOsmosis]

Originally posted by: rbloedow

Originally posted by: gopunk
wouldn't that be dangerous? it goes up with a starting velocity, so presumably it would come down with something close to that velocity?

No, all things fall at the same rate, once gravity is pulling the bullet down, it falls at a steady rate. This fallacy is also the logic behind the myth of throwing a penny off of the empire state building and it killing the person who's head it lands on.

All things don't fall at the same rate. They accelerate at the same rate, but that's only if you neglect air resistance. Things stop accelerating once they hit terminal velocity.

 

[rh71]

Originally posted by: Brutuskend

Things that make you go hmm....

rh71 hasn't killed his dumb self yet. Humm

Hmm... do you think your "another Brutuskend joke"..s are funny?

 

[Moonbeam]

The bullet reaches terminal velocity when the force of wind resistance which increases with the square of velocity equals the force of attraction from gravity. In a vacuum the bullet would hit with the same velocity it was fired. The velocity of the bullet, therefore, in air on earth, is a function of its aerodynamics and density if terminal velocity is reached.

 

[KingNothing]

Heh, I decided to look this up and it turns out a falling bullet can kill someone.

Everything that has been posted about the bullet's velocity being determined by gravity alone, and being the same as if it were dropped off a building is correct, however...


Text

A bullet fired into the air can climb two miles into the air and remain in flight for more than a minute. As the bullet falls, it reaches a speed of 300 to 700 feet per second. 200 fps is enough to penetrate the skull.


HowStuffWorks confirms the lethality but not the numbers

 

[gopunk]

Originally posted by: Moonbeam
The bullet reaches terminal velocity when the force of wind resistance which increases with the square of velocity equals the force of attraction from gravity. In a vacuum the bullet would hit with the same velocity it was fired. The velocity of the bullet, therefore, in air on earth, is a function of its aerodynamics and density if terminal velocity is reached.

yes, that is what i was getting at... glugglug's post seems to answer it nicely as well.

 

[dabuddha]

Haven't you seen The Mexican

 

[rh71]

Originally posted by: crab453
THIS can happen...

I met Joe during my "stay" at A. I. Dupont hospital in Delaware...He'll never be the same as he was before that night.

W O W. Unbelievable stuff.

 

[Moonbeam]

Hehe, gopunk, he not only had a good post, but for some reason I completely missed it the first time reading.

 

[ChrisIsBored]

Haha I love ATOT... where else will an innocent thread about guns and bullets turn into an argument?

 

[rh71]

Originally posted by: KingNothing
Heh, I decided to look this up and it turns out a falling bullet can kill someone.

Everything that has been posted about the bullet's velocity being determined by gravity alone, and being the same as if it were dropped off a building is correct, however...


Text

A bullet fired into the air can climb two miles into the air and remain in flight for more than a minute. As the bullet falls, it reaches a speed of 300 to 700 feet per second. 200 fps is enough to penetrate the skull.


HowStuffWorks confirms the lethality but not the numbers

Howstuffworks: good stuff.

 

[tcsenter]

wouldn't that be dangerous? it goes up with a starting velocity, so presumably it would come down with something close to that velocity?

A rifle bullet may ascend at a rate which exceeds the sound barrier, its not going to descend at anything remotely close to the speed of sound.

It comes back down and it can penetrate someone or something.

I've heard of people on news years eye shooting guns into the air and bullets coming back down and landing in peoples heads, backs, all kinda body parts.

Actually, what you've heard of are people who are shooting more horizontally than vertically. If you shoot a gun truly straight up into the air vs. a 45' angle, it will descend at a relatively slow speed and certainly will not penetrate anyone. It might leave a nice bruise on your head or crack a windshield.

I think the bullet would actually have more force on the way down because of all the potential energy it would build up during its ascent, which would add to all the energy it would build up going down.

Huh?? Man, you need to take your high school physics courses all over again. At the point the bullet's momentum transitions between ascent and descent, it has expended all force imparted onto it via the powder charge. It is, for all practical purposes, the same as being dropped from your hand at that height.

 

[rh71]

Originally posted by: glugglug
This principle works with small animals too. You can drop a mouse or hamster off the empire state building and the speed they reach in freefall is low enough they can walk away unscathed.

You guys don't recall seeing that video of the cat "flying" off the telephone poll (2-3 stories high) and landing safely on the concrete sidewalk before bolting away ? It was posted here about a month ago...

Granted, the Empire State Building isn't exactly 2-3 stories high...

 

[WinkOsmosis]

Originally posted by: rh71

Originally posted by: glugglug
This principle works with small animals too. You can drop a mouse or hamster off the empire state building and the speed they reach in freefall is low enough they can walk away unscathed.

You guys don't recall seeing that video of the cat "flying" off the telephone poll (2-3 stories high) and landing safely on the concrete sidewalk before bolting away ? It was posted here about a month ago...

Granted, the Empire State Building isn't exactly 2-3 stories high...

Cats spread out their limbs when they fall, reducing their terminal velocity. It would fall at the same speed from the Empire State Building.

 

[Brutuskend]

Don't feel bad rh71. We all have brain fade now and again. I once got into a mental state where I was thinking about what differant things smelled like. I could think of the smell for EVERYTHING except for one real common thing. For the LIFE of me I couldn't come up with what this very common thing smelled like!

So I took out my lighter and lit it and took a wiff.

I NOW know what FIRE smells like. It smells JUST LIKE BURNING NOSE HAIR!!!

 

[feralkid]

We talking Iraqi, or Kentucky cloud shootin' here?

 

[Cyberian]

Originally posted by: tcsenter
If you shoot a gun truly straight up into the air vs. a 45' angle, it will descend at a relatively slow speed and certainly will not penetrate anyone. It might leave a nice bruise on your head or crack a windshield.

That doesn't seem to fit with all the other information from other sites.

 

[Ender]

Originally posted by: crab453
THIS can happen...

I met Joe during my "stay" at A. I. Dupont hospital in Delaware...He'll never be the same as he was before that night.

Wow... that's preatty damn unfortunate.