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View Poll Results: Which Bullet will hit the ground first?
The bullet in his hand 31 28.70%
The bullet fired from the gun 4 3.70%
Both at the same time 70 64.81%
No idea. Stupid bloody question 3 2.78%
Voters: 108. You may not vote on this poll

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Old 07-05-2012, 08:55 PM   #61
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From typical eye height, it's probably more like 500 feet. Keep in mind that if the sights are aimed perfectly horizontal, the bullet actually travels upwards before it starts falling. The sights are accurate at two points in the bullet's path: once on the way up and once on the way down.
My head math sucks, lol. Looked up .45 ammo, about 1000 fps. At 5 feet, you're correct, it's just over 500 feet when fired perfectly level. Not enough for the curvature of the earth to come into play as was previously stated, which is what I was originally getting at. I was thinking it would have probably travelled 1500 feet or so.
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Old 07-05-2012, 09:47 PM   #62
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I'm going to ignore the whole argument regarding curvature of the earth, and throw another curve-ball into the mix. Perhaps some pilots could weigh in on this.


Assuming a perfectly flat and level ground, as the bullet approaches its own length's distance from the ground it will experience ground effect. During ground effect, the ground interrupts the vortices coming off of the bullet and the bottom half of the bullet experiences less drag than the top half, tilting it upward. This will result in the bullet gliding over the earth at a height of about an inch. It certainly won't do this for long, but the dropped bullet won't do this at all.

I'm voting that the dropped bullet will hit first.
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Old 07-05-2012, 10:15 PM   #63
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if the gun is rifled:
the spin will catch some air resistance and let it float a little. the still bullet will drop head-first, therefore it will fall faster.

if you're on an asteroid (or ief you have a really powerful gun (relativistic speeds)):
in theory, the bullet may fly into orbit (or break orbit) and never land. the still bullet will land as long as there is some gravity.

did any of you email your physics prof?

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Old 07-06-2012, 08:02 AM   #64
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if the gun is rifled:
the spin will catch some air resistance and let it float a little. the still bullet will drop head-first, therefore it will fall faster.
Typically these examples are set in a perfect vacuum. Otherwise we get responses like yours.
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Old 07-06-2012, 08:41 AM   #65
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9.8 m/s^2 or 32.2 ft/s^2 Gravity guys. Both at same time.
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Old 07-06-2012, 10:41 AM   #66
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Typically these examples are set in a perfect vacuum. Otherwise we get responses like yours.
then your head will explode. and i'd like to see a vacuum room large enough for a bullet to fly its course. especially if it's the gun used in eraser

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Old 07-06-2012, 11:37 AM   #67
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if the gun is rifled:
the spin will catch some air resistance and let it float a little. the still bullet will drop head-first, therefore it will fall faster.

if you're on an asteroid (or ief you have a really powerful gun (relativistic speeds)):
in theory, the bullet may fly into orbit (or break orbit) and never land. the still bullet will land as long as there is some gravity.

did any of you email your physics prof?
And bullets wobble, which actually makes them travel in a spiraling path (believe it or not). Depending on how the bullet comes out of the barrel can affect how much time it spends spiraling up vs spiraling down.
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Old 07-06-2012, 11:58 AM   #68
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then your head will explode. and i'd like to see a vacuum room large enough for a bullet to fly its course. especially if it's the gun used in eraser
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Old 07-06-2012, 02:25 PM   #69
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Old 07-06-2012, 02:35 PM   #70
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Its simple vectors. But long story short, according to the laws of physics, they SHOULD land at the same time. They both have gravity pulling them directly downwards making them both accelerate at a rate of 9.81 m/s/s, so when the gun is fired and the bullet is dropped, they both accelerate downward at the same speed. Now assuming they are at the same height, that alone tells you they should hit the ground at the exact same time. The bullet being fired from a gun accelerates in 2 directions however (straight downward and straight horizontally), assuming the gun is being held completely level with the ground, which is throwing you off, making you believe that it is in the air longer. The horizontal acceleration of the bullet however has no effect on the vertical acceleration.
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Old 07-06-2012, 02:47 PM   #71
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Its simple vectors. But long story short, according to the laws of physics, they SHOULD land at the same time. They both have gravity pulling them directly downwards making them both accelerate at a rate of 9.81 m/s/s, so when the gun is fired and the bullet is dropped, they both accelerate downward at the same speed. Now assuming they are at the same height, that alone tells you they should hit the ground at the exact same time. The bullet being fired from a gun accelerates in 2 directions however (straight downward and straight horizontally), assuming the gun is being held completely level with the ground, which is throwing you off, making you believe that it is in the air longer. The horizontal acceleration of the bullet however has no effect on the vertical acceleration.
that's true for newtonian physics. you know who trumped newton? einstein.

yeah, seeeeeeeeeeee


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Old 07-06-2012, 02:53 PM   #72
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that's true for newtonian physics. you know who trumped newton? einstein.

yeah, seeeeeeeeeeee

]
Yes, in a world of perfect physics that should be true. Im sure the vortex of air around the bullet being fired is significantly different than the bullet being dropped, so im guessing that will provide some sort of cushion to bullet being fired, making it hit the ground the slightest bit slower, but in a world of perfect physics, and in general newtonian physics, they hit the ground at the same time.
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Old 07-06-2012, 02:55 PM   #73
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that's true for newtonian physics. you know who trumped newton? einstein.

yeah, seeeeeeeeeeee

[IMG]http://hellogiggles.com/wp-content/uploads/2012/02/06/the_simpsons_testify_1.jpg[IMG]
Please, educate us on the inner workings of Einstein's theories Unless you're firing relativistic bullets then Newtonian mechanics works just fine.
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Old 07-06-2012, 02:58 PM   #74
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Please, educate us on the inner workings of Einstein's theories Unless you're firing relativistic bullets then Newtonian mechanics works just fine.
Well, he is correct if you want to get technical. The bullet vortex, difference in pressure surrounding the 2 bullets, and bullet rotation (Assuming the gun is rifled) all could play some sort of difference in the acceleration of the bullets as they travel towards the ground. Theoretically, Newtonian physics say they SHOULD hit the ground at the same time. That is in a perfect world however. In the real world, the bullets realistically could hit the ground at different times depending on all sorts of factors.
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Old 07-06-2012, 03:05 PM   #75
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Please, educate us on the inner workings of Einstein's theories Unless you're firing relativistic bullets then Newtonian mechanics works just fine.
http://en.wikipedia.org/wiki/Special_relativity
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Old 07-06-2012, 03:18 PM   #76
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Yes, in a world of perfect physics that should be true. Im sure the vortex of air around the bullet being fired is significantly different than the bullet being dropped, so im guessing that will provide some sort of cushion to bullet being fired, making it hit the ground the slightest bit slower, but in a world of perfect physics, and in general newtonian physics, they hit the ground at the same time.

Only if your "world of perfect physics" means that the earth is flat.
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Old 07-06-2012, 04:54 PM   #77
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is that you again, symmonds?
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Old 07-06-2012, 05:06 PM   #78
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Holy AP high school math problem...answer on your test is same time. No wind variable and gun held perfectly parallel to the plane/ground (x-axis).

Mythbusters might have done it but they can't disprove laws of gravity, physics, etc....


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Old 07-06-2012, 05:11 PM   #79
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Only if your "world of perfect physics" means that the earth is flat.
Not completely true...a bullet will travel so far that the earths tilt, sphere and whatnot don't impact the outcome even if all variables are included and not constants


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Old 07-06-2012, 05:51 PM   #80
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Not completely true...a bullet will travel so far that the earths tilt, sphere and whatnot don't impact the outcome even if all variables are included and not constants


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Go back a couple pages. For a regular gun that's correct (and I assumed as much for any projectile not entering orbit), but when you're dealing with high enough energy you actually have to take into account the curvature of the earth. The simple answer is "at the same time", the technically correct answer is "it depends".
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