Celebratory Gunfire Danger

Won’t there still be plenty of altitude for it to reach terminal velocity?

I personally shoot off one of my muskets when I want to celebrate. Instead of a bullet, I use a wadded up piece of toilet paper. The toilet paper wad goes up about 20 or 30 feet, and then floats gently back down to the ground while burning (while the kids all go ooh and ahh).

Don’t have to worry about shooting anyone when the bullet comes back down, and no danger of shooting myself in the foot either. :wink:

Yes to the first part, no to the second.

Imagine a cube. Now double the size of the cube. The wind resistance is going to be proportional to the size of a face of the cube, since that represents how much air is going to need to be pushed out of the way. The weight of the cube however is going to be proportional to the volume of the cube.

Double the size of the cube, and the wind resistance is going to increase by a factor of four. The weight of the cube however is going to increase by a factor of eight. Because the wind resistance doesn’t increase as quickly as the weight, the effect of wind resistance is smaller on larger objects. So the bigger object falls faster.

So while you are right that the wind resistance increases, the pull of gravity also increases. Both cubes would fall at the same rate in a vacuum, but in the atmosphere the bigger cube will fall faster, or at least it will once they fall far enough that they start getting closer to their terminal velocity.

So it kinda goes against what they teach you in high school physics, but bigger bullets fall faster.

The wikipedia page didn’t say what the round was, but some googling indicates that it was a 9mm handgun round. When mythbusters tested this round at it’s terminal velocity, it did not penetrate a pig’s head. Based on that, and the fact that the bullet that killed Shannon did penetrate her skull, I suspect that the round that killed her wasn’t fired straight up, but was instead fired at an angle.

My text that you quoted only applied to bullets fired straight up. As I said, fire it at an angle and the bullet will follow a parabolic arc and can easily have a fatal velocity when it returns to earth. There’s no argument that bullets fired into the air can be dangerous.

Thanks. Ignorance fought.

Regards,
Shodan

Actually - assuming we’re comparing the fall of a heavy object to a lighter one of the same size and shape - it does. At any speed above zero, the net downward acceleration of the heavier object is greater.

It’s well represented by the ballistic coefficient, which is a function of mass, density, cross-sectional area and drag coefficient.

Quite right.

High school physics has done quite a disservice by implying that drag can often be ignored. In the real world, especially when things are moving fast, assuming this reliably leads to wrong conclusions.

In particular, I’ve encountered quite a few smart people who don’t understand that, notwithstanding Galileo and that tower at Pisa, heavy objects do in fact fall faster than lighter ones (assuming sufficiently similar size/shape).

No: other things being equal, the heavy bullet will go higher, for the same reasons it will fall faster and reach a higher terminal velocity.

Isn’t that dependent on the propellant?

No. It would depend on muzzle velocity - but we’re assuming that is the same for both.

Eh. “Other things being equal” is fuzzy. Shodan might have meant the amount of propellant is the same, which for the heavier bullet indeed means lower muzzle velocity (unless you’re shooting at a black hole or something).

You are certainly right if you posit “assuming equal muzzle velocity,” but that introduces greater energy into one side of the calculation, which I would think bears mentioning explicitly.

I have been in the Middle East during celebratory fire and I can testify that it comes down and people do get injured and sometimes killed. I was in a house with a colleague in a Shia majority city in Iraq when Saddam Hussein’s sons were killed. Peole in this area hated Saddam and his sons and when the news broke they started shooting in the air. So many bullets were hitting our house that my friend and I initiall thought we were under attack.

Fair enough.

It’s interesting to consider the question of what happens when the bullets leave the gun with the same energy. Without air resistance, their peak heights would go as the inverse ratio of their mass, since potential energy is mgH. I’m not sure how to properly account for drag in this case.

Shooting guns in the air is stupid.

Early favorite for Retort of the Year (2012)

Every year on July 4th and New Years, prodigious amounts of gunfire can be heard in and around my neighborhood. (+/- 4 miles north of downtown Houston)
From the sound of it, I’m fairly certain that I’ve heard just about every caliber and type of weapon available to the average homeowner. (With some full automatic stuff occasionally. :eek:)
I have a, very large, (approx. 3,000 s.f.) ‘carport’ type metal roof on three sides of my house, when the gunfire starts I retreat underneath and listen for the bullets to impact.
I hear (on average) 3-5 bullets hit the metal roof every year.
The majority of the ones that I’ve found look to be 9mm or .38/.357 slugs, with an occasional .40 and .45 cal. (I don’t bother to look for the .22’s.)

Though I haven’t had one hit a ‘skylight’ yet, (plastic panels that let light thru) I make it a point to not stand underneath them. :wink:

Anecdotal: A friend that lives on the next street had a .45 cal. FMJ slug come down and puncture his aluminum carport roof, and then leave a ‘dimple’ the size of a quarter x 1/8" deep in the hood of a '64 Chevy Impala, a couple of years back. :mad:

That would have hurt! :frowning:

Actually, yes I did.

I assume you fire two bullets directly upward. One is a .22; the other a .44. You loaded your own ammunition, and put the same charge into each bullet. I would expect the .22 to go higher, but the .44 would fall faster. Is that correct?

Now assume two more shots. Same charge, but both are .44 caliber. One, however, is hollow so that it contains half the mass of the solid slug. Would the lighter one still go higher? I assume the answer is Yes, because the lesser mass is easier to accelerate for a given input of energy. Would the solid, heavier one still fall faster? I am guessing No, because wind resistance is the same for both.

Thanks, now my head hurts.

Regards,
Shodan

A local kid got hit by one this year.

Must be - given that it’s being launched at multiples of its terminal falling velocity, it seems very likely that it’s attaining a peak height well above that from which it will gain terminal velocity in falling.

Right, what I was getting at has already been hashed out by others, but it doesn’t matter how high different bullets go or how far they fall, they’re all going to reach terminal velocity on the way down, so all that matters is comparing that velocity and the bullets weights to see which packs more punch.

Some sort of hat would be in order I warrant.