>>>>>>>>>>>I am only grateful you do not live in one of the many cultures where firing AK47s into the air is a celebratory gesture <g>
>>>>>>>>>>
>>>>>>>>>>Aren't those the places where the Law of Gravity has been repelled and bullets do not come back down?
>>>>>>>>>
>>>>>>>>>Good point that, Alex. What DOES happen to the bullets once fired into the air? Assuming they travel several 100 meters, then fall back to earth (the latter is not just an assumption :-), I guess they would be pretty lethal landing on your head, made of metal and all - like dropping something off the Empire State Building.
>>>>>>>>
>>>>>>>>I do remember the MythBusters that was mentioned by someone else. I seem to remember the bullets not being lethal, and I seem to remember the "dropping something off of the ESB" being a myth too.
>>>>>>>
>>>>>>>http://www.straightdope.com/classics/a1_225.html
>>>>>>
>>>>>>That's all very well, citing a tumbling penny, but how about a streamlined bullet, or ball-bearing.
>>>>>
>>>>>He did say ignoring wind resistance, so in that case, if a penny reached a speed of 280 fps, then so would a bullet or a ball bearing (or a feather).
>>>>
>>>>Hey, I didn't say a wind-surfing penny, I said "tumbling". A penny landing edge-on would exhert a lot more pressure, I'd imagine.
>>>
>>>Ignoring wind resistance, it would exert the pressure of a coin at 280 fps. Now, I'm sure that would hurt like hell, but his point was that 280 fps is not very fast. It would probably hurt more on edge (more lbs per sq. ft), but still, if he is correct, it shouldn't do that much damage. Neither the bullet, nor the ball bearing would have any more speed than the coin, so shouldn't do much more damage than the penny, if any more at all. Given that there is, in fact, wind resistance, then the coin would likely not achieve 280 fps, while the bullet and the ball bearing would get a lot closer to it
>>
>>Sure, I did physics, Galilleo and his cannonballs from the Tower of Pisa and all that, but a bullet would have more mass than a penny, therfore more momentum.
>
>Not more momentum -- more force.

No, momentum is mass * velocity: the reason why a fist hitting a face does more damage to the face than vice versa - the fist, even though lighter than the face, because of its speed has a great momentum. The stationary face, although heavier than the fist, has no momentum.

Also, the fact that if you fell in the dock, between the wharf and a large ship, the ship only needs to just kiss you to break every bone in your body. Not much velocity but a HUGE mass combine to give a formidable momentum.

A bullet from a gun has a small mass but HUGE velocity - again combining to make a killer momentum.

The force acting on the dropped object, that which causes it to accelerate, is that of gravity.