Balistics question

[Dauphin]

Originally posted by Aeson


No, a bullet that loses it's velocity on the way up, to the point it reverses it's course or is just "falling", isn't going to have a high enough terminal velocity to do much damage. It's essentially a penny off a skyscraper at that point.

On a less steep trajectory the bullet can maintain a lot of it's velocity and do damage when coming back down... over yonder.

Coins and raindrops aren't going to injure you, but given that bullets are designed to be aerodynamic I'm not sure that you can say they won't pack a bit of punch when they hit you. 'course the .45 is probably less likely to be a problem.

[Lul Thyme]

Originally posted by SlowwHand


By now? How long have we known that what goes up comes down? Only an idiot can't figure that out.

The point is not that what goes up comes down, it's all about velocity.

The terminal velocity of a bullet is quite a bit less than its velocity coming out of gun, yet still probably dangerous.


We could probably make a gun shooting some object that would be lethal at close range yet the object would have so high air resistance that when it came back if we shoot the gun upwards, it would be safe.



Because of air resistance, the end trajectory would be much close to vertical than 45 degrees and as such, the velocity of the bullet would probably be very close to terminal velocity (which is of course MUCH higher for a bullet than a penny).

[LordShiva]

Guns don't kill people, holes kill people.

[Aeson]

Originally posted by Dauphin
Coins and raindrops aren't going to injure you, but given that bullets are designed to be aerodynamic I'm not sure that you can say they won't pack a bit of punch when they hit you. 'course the .45 is probably less likely to be a problem.

Bullets are designed to be aerodynamic in a specific fashion. A falling bullet has lost the effect of any rifling, and also tends to fall on it's side.

Mythbusters did a show on this and another on falling pennies. The terminal velocity for the bullets were ~100mph. For the pennies it was more variable, at the upper end they got ~60mph. Given their different mass, that is a noticeable difference, but in regard to the question asked in this thread, both are essentially the same.

It's a small bit of metal going fast enough to hurt a bit, but isn't going to kill you. Terminal velocity isn't fast enough, and not enough mass.

[snoopy369]

One minor nitpick: The velocity will not kill you. The force would, if it did. Mass is an equal part in that equation... so a very heavy bullet would most certainly do more damage than a lighter one (for the same terminal velocity) (as Aeson implies at the end of the last post).

[Lord Avalon]

Mythbusters

[Kuciwalker]

Originally posted by Aeson
Bullets are designed to be aerodynamic in a specific fashion. A falling bullet has lost the effect of any rifling, and also tends to fall on it's side.

(its its its its its its its its its its its its its)

[Aeson]

No Kuci, I only needed one its.

[Lancer]

Originally posted by VetLegion


A nitpick, but if I remember my physics correctly, the acceleration of the bullet is proportional to earth's gravity and does not depend on the weight of the bullet
If not for wind resistance a feather and a bullet would fall at the same time.

Aeson, so it's something smaller than...oh a bowling ball but bigger than a .45 slug that will kill you...

[Wiglaf]

Originally posted by Lord Avalon
Mythbusters

You might as well give a thumbs up to Hitler. Nothing Mythbusters has ever said is accurate. The show once claimed that driving your car into an ocean will not result in drowning because of some technobabble about pressure equalizing. I suggest no one listen to Mythbusters, what is it, some sort of take off on Ghostbusters? The show should be called ****tingonFacts instead to avoid confusion.

[Dry]

http://en.wikipedia.org/wiki/Celebratory_gunfire

[Lul Thyme]

Originally posted by Aeson


Bullets are designed to be aerodynamic in a specific fashion. A falling bullet has lost the effect of any rifling, and also tends to fall on it's side.

Mythbusters did a show on this and another on falling pennies. The terminal velocity for the bullets were ~100mph. For the pennies it was more variable, at the upper end they got ~60mph. Given their different mass, that is a noticeable difference, but in regard to the question asked in this thread, both are essentially the same.

It's a small bit of metal going fast enough to hurt a bit, but isn't going to kill you. Terminal velocity isn't fast enough, and not enough mass.

It seems you are only remembering the cases you want...

Wiki says that Mythbusters confirmed that, in practice, the bullets will often keep some of their spin, reducing the effect of air resistance and keep lethal velocity. They also confirmed NUMEROUS recorded deaths from bullets fired more or less upwards in the air.

[Lancer]

Our hero doesn't have to go to work tomorrow then?

[VetLegion]

Originally posted by snoopy369
One minor nitpick: The velocity will not kill you. The force would, if it did. Mass is an equal part in that equation... so a very heavy bullet would most certainly do more damage than a lighter one (for the same terminal velocity) (as Aeson implies at the end of the last post).

A nitpick: mass is not an equal part of the equation. Kinetic energy of a bullet is Ek = 0.5 * m * v^2, meaning that increasing velocity increases the energy much faster than increasing mass.

[Zoid]

Originally posted by Lul Thyme


It seems you are only remembering the cases you want...

Wiki says that Mythbusters confirmed that, in practice, the bullets will often keep some of their spin, reducing the effect of air resistance and keep lethal velocity. They also confirmed NUMEROUS recorded deaths from bullets fired more or less upwards in the air.

Indeed. The case of bullets landing on their side was only the effect of them being fired at an exact 90 degree angle. And that's close to impossible to do without some form of stabilising rig like the one they used in that episode.