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Plat4PoP
RealPoor Jedi
Joined: 12 Oct 2002
Posts: 14376
Location: USA
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Paco
RealPoor Jedi
Joined: 13 Oct 2002
Posts: 12940
Location: Jacksonville, FL
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 Posted: 11/25/03 - 11:57 Post subject:
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hahahaha
i love it
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Abi
RealPoor Sensei
Joined: 11 Aug 2003
Posts: 1747
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Posted: 11/25/03 - 12:15 Post subject:
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Karma owns...
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Jinu
RealPoor Guru
Joined: 11 Oct 2002
Posts: 2396
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Posted: 11/25/03 - 13:21 Post subject:
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holy shit, i had no idea a falling bullet was that powerful.
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WheresNWS
RealPoor Master of Posts
Joined: 19 Nov 2002
Posts: 6448
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Posted: 11/25/03 - 13:35 Post subject:
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I didn't know they even still had those rallies. 
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BlingBling
Toomuchtimeonhands
Joined: 20 Dec 2002
Posts: 944
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Posted: 11/25/03 - 13:36 Post subject:
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ok so the bullet was in the air how long?
im guessing a while being time X
X/2=t where 9.8*t was the velocity the bullet was capable of reading.
Depending on the air and coefficient of friction of the bullet it may have encountered its terminal velocity,
lets just say thats one f*****g fast bullet
in perfect conditions, ie, no drag ect......the bullet struck him at hte same velocity it left the gun... physics are phun
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Paco
RealPoor Jedi
Joined: 13 Oct 2002
Posts: 12940
Location: Jacksonville, FL
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Posted: 11/25/03 - 13:38 Post subject:
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picture dropping a penny from the top of the empire state building
same result, cept even more
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Jinu
RealPoor Guru
Joined: 11 Oct 2002
Posts: 2396
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Posted: 11/25/03 - 13:46 Post subject:
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dropping a penny off the empire state building doesn't kill anyone because of air resistance
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Jakanden
RealPoor Master of Posts
Joined: 11 Nov 2003
Posts: 5334
Location: Fuck if I know - I am always lost
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Posted: 11/25/03 - 13:56 Post subject:
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What a f*****g d*****s heh.
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Banzai
Guest
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Posted: 11/25/03 - 14:40 Post subject:
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This makes baby Jesus chuckle to the point of blowing Mary's breast milk out his nose.
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Tolanin
RealPoor Guru
Joined: 16 Oct 2002
Posts: 3551
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Posted: 11/25/03 - 15:00 Post subject:
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bullet prolly reached terminal velocity.. a bullet from a gun goes a few times the speed of sound... still though thats pretty f****n fast.
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Norrick
Luke Warm
Joined: 08 Oct 2003
Posts: 200
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Posted: 11/25/03 - 15:03 Post subject:
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What are the chances of that happening? I bet that guy feels pretty stupid right now. 
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Faerdal
Toomuchtimeonhands
Joined: 11 Oct 2002
Posts: 954
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Posted: 11/25/03 - 15:47 Post subject:
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it's been awhile since i've done anything with physics.. but the pull of gravity is constant, and the vertical velocity of an object that's moving unpropelled through the atmosphere is purely a function of time then, correct? so assuming terminal velocity wasn't reached, wouldn't any object launched skyward with an initial velocity X be at the same velocity X when it hit the ground again? gravity is acting upon it for an equal amount of time during the rising and falling parts of the arc (and the maximum height of travel is only a function of the initial velocity).
i dunno, does that sound right? if so, the bullet basically hit his skull with the same velocity as one fired from point blank range. it probably didn't hit head on either, it may have been tumbling. (i dont know enough about fluid dynamics to figure out if the bullet is aerodynamically shaped in such a way to force it, while falling, into a natural axis-directional spin such as when fired from a rifled barrel)
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WheresNWS
RealPoor Master of Posts
Joined: 19 Nov 2002
Posts: 6448
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Posted: 11/25/03 - 15:55 Post subject:
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You all are underestimating terminal velocity. True that in a vacuum, the bullet would be travelling as fast downward as upward when it hit the ground but air plays a big role.
http://hyperphysics.phy-astr.gsu.edu/hbase/airfri2.html#c5
Put in radius=.01m
density = 10000kg/m^3 (~lead)
The terminal velocity is around 63 miles/hour. It would hurt, but wouldn't kill you. Unless you're a p***y like scrotum. Then it would be certain death.
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Jinu
RealPoor Guru
Joined: 11 Oct 2002
Posts: 2396
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Posted: 11/25/03 - 15:55 Post subject:
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ok, whatever the muzzle speed is, the bullet goes almost straight up, rapidly decreasing in speed due to gravity, air resistance, etc.
At some point many yards in the air, the bullet has no velocity. From that point it descends, accelerating at the rate of gravity minus air resistance.
So I don't think the speed of the bullet on impact has any relation to the speed the bullet was travelling when it was fired.
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Syke
RealPoor Guru
Joined: 12 Oct 2002
Posts: 2976
Location: Huntington Beach, CA
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Posted: 11/25/03 - 16:02 Post subject:
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The ascending or initial velocity would not match the velocity of the falling bullet at point X, simply because there was no initial force (besides gravity) applied to the bullet during it's descent, or at the start of it's descent. It depends on how fast the gun can actually propel the bullet. (e.g. faster than the earth's gravitational pull can drop the bullet from 0% acceleration, starting from the apex of it's flight.)
I don't know if that made any sense either, but uhh..ya. I think that's right :X
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Nahualli
RealPoor Master of Posts
Joined: 11 Oct 2002
Posts: 8461
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Posted: 11/25/03 - 16:02 Post subject:
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it might have a small effect in that a bullet that was fired at a slower speed would not have gone as high not giving the bullet on its way down as much time to accelerate.. given air resistance the higher up you are the more you will accelerate assuming it takes a certain distance to achieve terminal velocity.
which by the way is a real cool game in DOS.. right up there with Radix.... good times
-Nah-
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Spitulski
RealPoor Guru
Joined: 23 Nov 2002
Posts: 4345
Location: Washington
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Posted: 11/25/03 - 16:14 Post subject:
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Bullet leaves the gun at a few times it's innate terminal velocity would allow. Gravity/resistance/drag/etc slows that down to a stop when shot straight up. At this point, the energy that the bullet had when fired from the gun that allowed it to reach it's velocity is gone, and the only energy it has is potential energy via gravity x mass. Thus, it can only obtain terminal velocity - not as fast as when it was fired from the gun.
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Paden
RealPoor Master of Posts
Joined: 23 Oct 2002
Posts: 9362
Location: North CAROLINA!
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Posted: 11/25/03 - 16:22 Post subject:
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that poor guy
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WheresNWS
RealPoor Master of Posts
Joined: 19 Nov 2002
Posts: 6448
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Posted: 11/25/03 - 16:23 Post subject:
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63 mph. kthx.
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Syke
RealPoor Guru
Joined: 12 Oct 2002
Posts: 2976
Location: Huntington Beach, CA
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Posted: 11/25/03 - 18:09 Post subject:
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| WheresNWS wrote: | | 63 mph. kthx. |
We didn't need an exact answer thx.
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GruntingCod
RealPoor Master of Posts
Joined: 11 Oct 2002
Posts: 6399
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Posted: 11/25/03 - 18:13 Post subject:
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| Jinu wrote: | | holy shit, i had no idea a falling bullet was that powerful. |
I was in Mexcio one time, and it was during some like parade and like a bunch of crazy mexicans were shooting in the sky. I was only like 8, but I remember the car we rented was hella dented.
It was also on that one movie with Brad Pitt where he had to get a Gun or some shit.
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Faerdal
Toomuchtimeonhands
Joined: 11 Oct 2002
Posts: 954
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Posted: 11/25/03 - 19:09 Post subject:
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| Jinu wrote: | ok, whatever the muzzle speed is, the bullet goes almost straight up, rapidly decreasing in speed due to gravity, air resistance, etc.
At some point many yards in the air, the bullet has no velocity. From that point it descends, accelerating at the rate of gravity minus air resistance.
So I don't think the speed of the bullet on impact has any relation to the speed the bullet was travelling when it was fired. |
i was dramatically underestimating terminal velocity due to air resistance (i'm still not sure 63mph is entirely accurate too, heh). but neglecting the air resistance, any object thrown/shot/fired/whatever off the surface of the earth will impact the earth at the same speed as it left the ground with at Time=0. gravity acts as a decelerant as the object rises, and an accelerant as it falls. the force applied throughout the entire trip is constant, 32ft/s/s. therefore the total deceleration caused as the object rises is equal in magnitude to the total acceleration as it falls. with no air resistance, an object travelling in an arc (straight up and down is also an "arc") will have the same magnitude of velocity (but opposite sign) at all points on the arc where the height above ground is equal. the only force that is acting on a (non-self propelled, non-deflected) object in a vacuum is gravity. the muzzle velocity thus has a direct bearing on the final impact speed of a falling bullet, higher initial velocity equals more velocity that gravity has to overcome in order to "stop" the bullet. thus a higher apex for the arc. thus more time for the fall. thus more total acceleration due to gravity.
i didn't think the terminal velocity of a falling bullet was anywhere near 63mph though, i was assuming it'd be much much higher. hence the pseudo-ignoring of the air resistance that i did. ;)
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ATM Banana
RealPoor Master of Posts
Joined: 02 Jan 2003
Posts: 8575
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Posted: 11/25/03 - 19:48 Post subject:
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this thread was interesting, but got boring.
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Luturb
RealPoor Guru
Joined: 11 Oct 2002
Posts: 4043
Location: Livermore, California
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Posted: 11/25/03 - 20:23 Post subject:
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| Syke wrote: | The ascending or initial velocity would not match the velocity of the falling bullet at point X, simply because there was no initial force (besides gravity) applied to the bullet during it's descent, or at the start of it's descent. It depends on how fast the gun can actually propel the bullet. (e.g. faster than the earth's gravitational pull can drop the bullet from 0% acceleration, starting from the apex of it's flight.)
I don't know if that made any sense either, but uhh..ya. I think that's right :X |
Not True. The only think stopping the bullet from going up was the accelleration of gravity (plus a small amount of friction). So in a vacuum, a bullet falling for the amount of time it took to slow down to zero, with the same accelleration that slowed it down in that time, would get it back to the same speed it was going when it left the gun. The bullet is so small though that friction from the air slows it down a lot.
63 mph is nowhere near the speed of a bullet, but it's still faster than I want something slamming into my head.
Another phun physics question.
If you fire a bullet from a gun, with level trajectory and nothing in the way of the bullet, at the same instant that you drop another bullet from the height of the gun, which bullet hits the ground first?
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WheresNWS
RealPoor Master of Posts
Joined: 19 Nov 2002
Posts: 6448
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Posted: 11/25/03 - 20:38 Post subject:
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| Luturb wrote: | | If you fire a bullet from a gun, with level trajectory and nothing in the way of the bullet, at the same instant that you drop another bullet from the height of the gun, which bullet hits the ground first? |
Does this magic bullet have wings?
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Tolanin
RealPoor Guru
Joined: 16 Oct 2002
Posts: 3551
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Posted: 11/25/03 - 20:39 Post subject:
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size really has nothing to do with how much its slowed down.. surface area and mass affect it.. so a car with the same porportional surface area - mass as a bullet would be slowed down equally as much.
this thread got way to complex for simple shit ;p
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Faerdal
Toomuchtimeonhands
Joined: 11 Oct 2002
Posts: 954
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Posted: 11/25/03 - 22:24 Post subject:
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| Luturb wrote: | Another phun physics question.
If you fire a bullet from a gun, with level trajectory and nothing in the way of the bullet, at the same instant that you drop another bullet from the height of the gun, which bullet hits the ground first? |
They both hit the ground at the same time. The horizontal velocity vector has nothing to do with the vertical one, and gravity still pulls downward at the same 32ft/s/s on both bullets =)
Man, I was bored to hell with this stuff when I had to take the classes for it. Now that it doesn't mean jack shit, it's actually pretty interesting. I should have taken the more advanced physics classes in college, maybe minored in it just for fun. I probably could have been pretty good at it, if I could have gotten past the whole educational system mental block attitude I had.
(edit/add: your question could also be phrased as somewhat of a trick. we're obviously talking about a theoretically flawless system that discounts for any oddities in the natural curvature of the earth such as hills or bumps. if so, then the bullet fired from the gun would hit a microsecond after the dropped one, due to the slight extra distance it would have to fall after accounting for the curvature of the earth at some point a mile or two off in the horizon.)
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BlingBling
Toomuchtimeonhands
Joined: 20 Dec 2002
Posts: 944
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Posted: 11/25/03 - 22:51 Post subject:
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advanced physics has nothing to do with this kinda stuff, this is high school physics
basically all that is based of 2 equations which can be written in terms of x or y being vertical or hoizontal values.
oh and everyone who added shit to this has yet to add anything to what i origonally presented
f**k you all
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WheresNWS
RealPoor Master of Posts
Joined: 19 Nov 2002
Posts: 6448
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Posted: 11/25/03 - 22:53 Post subject:
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| BlingBling wrote: | advanced physics has nothing to do with this kinda stuff, this is high school physics
basically all that is based of 2 equations which can be written in terms of x or y being vertical or hoizontal values.
oh and everyone who added shit to this has yet to add anything to what i origonally presented
f**k you all |
Shut the f**k up, moron.
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