Would a bullet travel farther in a vacuum?

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in components, the sum of forces in the x direction: Force friction from air due to motion in the x direcction. Thats it. (If it weren't for gravity and friction, the bullet would travel forever. ) IN the y direction (which determines range, which we're interested in.) you've got the force of gravity, negative, and technically, friction due to motion in air, positive.

Frictional forces resist the direction of movement. Because the bullet is traveling at a some initial velocity in the x direction, friction due to air resists this motion in the x direction. Because the bullet is accelerating downwards in the y direction, the friction due to air resists this movement by adding a slight force up.

I admit this isn't the best representation, because air is a fluid, not a solid surface.

Geckgo,maybe the drag equation here will solve your woes? http://en.wikipedia.org/wiki/Drag_(physics)#Drag_at_high_velocity here is much more suitable to find the forces at work.
 
already on top of it, but trying to put it together to solve this problem has pains of it's own. When you convert the drag equation (I got a velocity vs time equation from it) to find distance, it involves a horrible integral that I'm not doing out here. Even the velocity vs time equation is a mess, because using that simple drag equation for a changing velocity is a PITA. Thank you for the link, but I've got that part. You may have noticed all those arctangents, e exponents and such, those come out of the diffeq and integrations. The raw equations aren't enough for this problem I don't think.

Edit: If I had my big calculator, I could cheat and use the v(t) equation and fudge some bullet values into it, but my wimpy RadioShack calculator isn't really up to the task
 
The simple answer is air friction is relevant to horizontal distance traveled. I did not take time to work the math, but as our planetary gravity accelerates objects equally at 32 feet per second2, the air friction on the vertical component is insignificant and can be ignored unless the bullet is falling several miles.

The first ballistic chart I Googled provides the solution.
A 50cal 750 gr A-Max fired at 2,800 feet per second slows to 1,565 FPS by 1,500 meters. It travels that distance in 2.35 seconds. Without air friction it would have traveled at the original 2,800 FPS for the same 2.35 seconds and covered 2,005 meters. Bullet drop remains the same -893 inches in either case.
 
Simple Newtonian physics will provide the answer to this one.

It will travel farther in a vacuum.

An object in a constant state of motion will remain in a constant state of motion unless and until it encounters an outside force. Here, Newton is describing Conservation of Momentum. If no outside force is present, momentum will be conserved forever. Fired in outer space, away from the gravitational field of any massive object, and not influenced by atmosphere...the bullet will continue to travel at the speed it was moving at the instant it left the muzzle forever...unless it strikes something or falls under the gravitational influence of a stellar body.

Of course, that statement is purely theoretical, because even "empty" space has things in it, and sooner or later...the bullet will hit something. Even a speck of dust represents an outside force, and hitting that tiny spec of dust will change the bullet's speed and momentum. Over the course of a few million years, it could hit enough specks to destroy all the momentum that it had initially.

Fired in a vacuum, but in a gravity field...there is one outside force that still applies, but the other one...frictional resistance from the air...is missing. The bullet will travel farther.
 
Just curious, would there be enough oxygen in the cartridge casing to facilitate combustion? I would think so, since weapons can be fired underwater. However, if a weapon was fired in a vacuum, it would no longer be a vacuum since you have introduced outside factors into the atmospheric conditions...correct?- I am referring to man made conditions, and not space.
 
The question is one of lift and drag. Because the bullet is symmetrical, the air pressure on the top and bottom are the same. That means no lift in air, so a bullet in a vaccuum will go farther because there is no drag.

If the question was about a Frisbee being thrown in a vacuum, you'd get the opposite answer.
 
travel farther in a vacuum?

Well, is the vacuum made of metal, or a new-fangled plastic one? Either way, I think traveling through it will slow a bullet down.

;)

Back on topic, no air = no air-resistance.
 
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Potassium Nitrate is a component in black gunpowder.

Modern smokeless gunpowder is Nitrocellusose (with Nitroglycerin if it is a double base powder).
 
guys, let's stay focused, your baseballs and atheletes are preforming better primarily do to a different gravitation force rather than the miniscule difference in air pressure. If you go high enough you get into what is called geosynchronous orbit, which is another matter entirely.. back to the regular programming.
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Uh... yeah... That explains why alien rocket boosters are required to keep the moon in orbit around the planet.. since gravity clearly isn't doing it.

Geosynchronous and Geostationary orbits have nothing to do with a lack of gravity and functions by matching the earths rotation period to the orbital velocity of the satellite. The higher altitude is required by simple principles which require an object at a fixed velocity to travel a longer circuit in order to return to the same position at the same time when compared to a slower object.

Now, that's not to say that the effect of gravitation doesn't decrease with distance, but not nearly at the rate you suggest. For example, Denver experiences 99.94% sea level gravity... while at the same time, only about 82% of the atmospheric density of sea level.

Air density is in fact the answer to why balls can be more readily hit further at higher altitude.

And to stay on topic, yes, a bullet fired in a vacuum will fly farther than one fired with atmo.


Slightly on topic, my favorite game quote ever:

""I dare to assume you ignorant jerkwads know that space is empty. Once you fire this hunk of metal, it keeps going until it hits something! That can be a ship, or the planet behind that ship. It might go off into deep space and hit somebody else in ten thousand years! If you pull the trigger on this you are ruining someone's day, somewhere and sometime!"

- Alliance Sergeant"
 
The bullet would go on forever at that speed until a larger object changes it's course if gravity is not present.
 
The bullet would go on forever at that speed until a larger object changes it's course if gravity is not present.
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For sake of arguement, no. Small objects can chip away at velocity too. Case and point, bullets slow down in air, which is millions (read: Trillions, Quadrillions, maybe more) of times smaller than the bullet.
Off topic: And for added fun, I am now officially announcing that it is in fact the bullet that stays stationary, and the planet that circles due to the explosion of the gun powder, moving the target towards the stationary bullet.
 
Air density is in fact the answer to why balls can be more readily hit further at higher altitude.

After researching, I stand corrected. Just goes to show that bad physics professors can plant seeds of misconception that last for years.
 
Well, if you really want to factor in air resistance, start with a perfectly cylindrical projectile.

Oh, and if you want to muddy this speculation up, recall that the time measurement used will be affected by whether the shot is spinward or anti-spinward with or without atmosphere.
 
Definitely. I'm not sure where I got the number, but a physicist calculated the affect of air resistance on flying objects is about 125 times greater than that of gravity.
 
Why hasn't a space travel corporation ie. NASA fired guns in space. or have they?

Would love to see that. ".357 magnums in space.....with Buck Rogers..." The muzzle blast would be beautiful.
 
You can get "lift" out of a bullet trajectory if it is fired at a steep downward angle. Basically because of the same idea the op had. Might keep this in mind if plinking cans from the top of the grand canyon.
 
The best way to answer this is with another question. Does a bullet slow down along it's flight path? If so is air the reason why? The answer to both questions is yes so a bullet fired in a vacuum would go further.
 
Geckgo said:
Air density is in fact the answer to why balls can be more readily hit further at higher altitude.

After researching, I stand corrected. Just goes to show that bad physics professors can plant seeds of misconception that last for years.
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Indeed, the difference in gravity between the highest point on the planet and the lowest point on the planet is basically negligible.
 
I seem to remember a video from a moon landing show that a feather and something else (heavy) hit the ground at the same time when dropped.

In physics class they had a device (on earth) that would chunk a ball bearing out with a spring at the same time it dropped one out the bottom. They hit the floor at the same time but apart.

That being said if you fired a bullet in a vacuum, it would go further due to simple drag and pressure. I now wonder what powder burn rate charts would look like inside a vaccum.
 
This kind of reminds me of an old bench rest shooter friend that engaged me in an argument about bullet rise. He was insistent that a bullet rises after leaving the muzzle and would hit the ground at a different time, than a bullet being dropped from the same exact hight from the ground. In all the years of loading and shooting with him I never was successful in educating him about trajectory, or the fact that the air pressures is equal on all sides of the spinning bullet because there is nothing about the shape of a bullet that provides any lift. To attain lift it requires higher air pressure on the under side of the bullet and lower air pressure on the top side of the bullet to create what is refered to as lift, which is accomplished by air foil. Very simple fact of the physics involved if one gives it just a minimal degree of thought.
gamestalker is offline
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I had the same trouble with a guy at work. He just couldn't understand the fact that if you zero your scope for 200 yards and then shoot it "horizontally", you're not actually launching the bullet parallel to the line of sight represented by the scope axis, you're launching it "up" a tiny fraction.

There's also the matter of precession. The spin of the bullet changes the trajectory slightly. The bullet doesn't actually go "straight".

If a bullet doesn't go "up" beyond the close in zero how can it ever fall " back" for the second zero?

Most shooters use both sides of the parabola.
 
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