GTA
General Discussion To Gateway To Airguns => Airgun Gate => : August 06, 2006, 10:20:01 PM
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Random quote: if a pellet is going 800fps, and a bullet shot at the same time is going 3000fps, with a level shot, which one hits the ground first?
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My little brain thinks they will hit the ground at the same time.
But it does not sound right. :0
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They both hit the ground at the same time. One is just two miles farther down the road.
Bart.
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Wuthout getting into issues of possible lift thrugh roatation adn wind direction, this is the classic physic's class example....fired level, horizonatal vel. doesn't effect vertical vel. (gravity in this case)...so if fired from the same height over level ground, will hit ground (vertical velocity) at the same time.
Of course that only really works in a vaccuume, are little games rotating cylnders play in atmosphere that can change that by a small amounts.
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...and remember that we live on a round ball, not a "flat earth"....
The 3000fps bullets takes longer to hit the ground, about 20ms (.02 sec) than the slower speed pellet, assuming it's fired from about a 5' height off the ground. Why? Because of the curvature of the earth's surface, the earth starts "falling away" from the bullet as the bullet travels in a horizontal direction... the further the bullet travels, it actually has farther to drop.
Theoretically speaking, one can shoot a bullet so fast that it NEVER hits the earth - that's called "escape velocity". NASA does it all the time (sorta)...
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This is of course if both objects are shaped the same and are of the same mass. Correct?
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That's not very significant, since the vertical drop (and vertical velocity) we're talking about is rather small and the densities are (roughly) comparable, the atmospheric phenomena of air resistance and boyancy don't really come into play.
The projectiles will only take on the order of .6 sec to hit the ground, at a speed of about 19 feet/sec, or about 12-13mph.
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vinceb - 8/6/2006 11:33 AM
...and remember that we live on a round ball, not a "flat earth"....
The 3000fps bullets takes longer to hit the ground, about 20ms (.02 sec) than the slower speed pellet, assuming it's fired from about a 5' height off the ground. Why? Because of the curvature of the earth's surface, the earth starts "falling away" from the bullet as the bullet travels in a horizontal direction... the further the bullet travels, it actually has farther to drop.
Theoretically speaking, one can shoot a bullet so fast that it NEVER hits the earth - that's called "escape velocity". NASA does it all the time (sorta)...
I realy doudt the curvature of the earth is a reasonable factor to consider.
The curve is small enough that, over the distances we are talking about it would be completely swamped by local variations...random rises and falls in ground level...hills.
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Let's see if I got this right...
I believe that the earth curves approximately 8 inches per mile.
One mile is 1760 yards, so over a normal shot of say, 25 yards, one could expect a drop of roughly 0.1 inches due to durvature of the earth.
so grab those mildots and make your corrections! =D
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If we're trying to get *really* accurate, I think you're all forgetting that gravity varies from point to point depending what kind of material the earth is made of at any given point.
This could swamp the curvature factor in mining areas, I'd think.
:p :p
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Ok, let me end this since I instigated it in the first place:)
Let's just ASSUME that our tiny parcel of land has been calibrated from crust to magma core for consistency, and has been completely flattened smooth as glass. The projectiles are of the exact same shape(round), and there is no air, astronauts or squirrels in the way, the barrels have been leveled with special atomic calipers and the triggers are both being fired electronically from the same switch, which is wired in paralell to the triggers. So all we are dealing with is forward velocity and gravity! I would have put this ALL in my quote if I had more time and space to write it.
they both hit the ground at the same time, no split hairs, or logs, or cheerleaders doing the splits.
Dan
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....the acceleration due to gravity (in a vacuum) is independent of mass.
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I'd go with that.
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I said no text!