While we were driving over to the mall today, my 12 year old son asked me; “What would happen if you fired a gun from top of the Empire State Building down to the ground?”
My not-so-sensitive thirteen year old son said that it would probably go straight through some dumb jerk who was standing around and doing nothing. That brought a chorus of other 13 years olds to describe the bloody mess, arrest, murder trial etc…To which the 12 year old said: no, really what would happen?
I had to punt saying that it depended upon the caliber of the gun, wind and weather, if it hit anything on the way down etcetcetc. Not satisfied, he asked if I could post this question on SDMB. So here it is…anyone got an answer?
I’m not sure I see what the point of contention here is. Clearly it could kill someone. Are you wondering just precisely how fast the bullet would be going? I would expect that even though the bullet is falling, it would actually slow down on its way down, due to air resistance and the fact that its initial velocity would be much greater than its terminal velocity. Just how fast it would be going I’m not prepared to say, hell, I don’t even have a good idea of how fast bullets go to begin with, but I imagine some physicist will be along to give you a good estimate.
If the gun was a low-power, short range weapon (think derringers and Saturday-night-specials), at some point, the air resistance to the bullet would overcome the initial charge and the bullet would continue to fall at its “terminal velocity” (the speed at which wind resistance matches the effect of gravity).
If the gun had any sort of power, the bullet would strike at something near its normal velocity for that range, perhaps a tiny bit faster. The Empire State building is slightly shorter than a quarter mile high (excluding the aerial at the top), so a weapon capable of going 1/2 mile or one mile in “normal” flight is not going to suffer the effects of terminal velocity when it has gravity aiding it.
Thanks for the sites. I showed them to him. He wanted to know if the bullet would go thru the sidewalk or break into bits like a glass bottle. I told him that it probably would put in a big dent in the sidewalk concrete as well as smash the bullet itself. I guess the bullet wouldn’t break into smithereens. He seemed satisfied. So thanks again for your help.
An old fashioned lead “ball” or even a “minnie” would spall the concrete, but not seriously damage it. A harder round would gouge out a good-sized hole, but would not really go through the sidewalk unless it was designed as an armor-piercing round. (I’ve made the assumption throughout that we’re discussing handguns or rifles. A cannon could have a lot more serious effect.)
Think of photos of street fighting or the walls behind a firing-squad’s target. The bullets were shot by fairly high-powered rifles from much closer than 1/4 mile. That is the damage that might result from a similar round fired from 1/4 mile with a slight gravity assist.