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- Jim

Things that make you go.....hmmm?

That comic has recently gone on the anti-hunting campaign...

But that one was kind of funny, and you can read a bit into it, derogatory too

I don't always agree with the cartoonist's political positions, but I like his sense of humor.

- Jim

Methinks young Jeffery needs to be introduced to a few of the "girls" on this forum.

IIRC, a gun will fire on the moon. The recoil will probably send you flying, though.

Kerbouchard wrote:IIRC, a gun will fire on the moon. The recoil will probably send you flying, though.

Because the masses involved are the same, recoil would be exactly the same as on Earth.

KBCraig wrote:

Kerbouchard wrote:IIRC, a gun will fire on the moon. The recoil will probably send you flying, though.

Because the masses involved are the same, recoil would be exactly the same as on Earth.

but you wont be firmly planted

lunchbox wrote:

KBCraig wrote:

Kerbouchard wrote:IIRC, a gun will fire on the moon. The recoil will probably send you flying, though.

Because the masses involved are the same, recoil would be exactly the same as on Earth.

but you wont be firmly planted

Sure you will. Physics work the same. It's not like being under water where you have a viscous material preventing your mobility. As long as your center of gravity is distributed between your feet the same as it is here you are just as "firmly planted".

I am sure the recoil would feel different because you are "lighter" in terms of weight but the recoil would not likely knock you over unless you were shoulder-firing a 10 gauge shotgun or something like that.

Noting the reduced gravity and no frictional losses due to moving through air, the bullet would go a LONG way. Depending on the direction in which you fired it, it may not ever stop until it hit another object (in which case it may ricochet and continue going indefinitely), it may end up orbiting the moon, it may end up eventually in the ground on the moon if the angle is low enough for gravity to defeat the inertia of the bullet, it may go off into space and never stop, or it may end up caught in the earth's gravity and burning up in the earth's atmosphere.

Kind of an interesting thought.

mr.72 wrote: Sure you will. Physics work the same. It's not like being under water where you have a viscous material preventing your mobility. As long as your center of gravity is distributed between your feet the same as it is here you are just as "firmly planted".

That seems correct assuming the muzzle velocity is the same, which it would probably be pretty close assuming the cartridge holding air thing worked (which we will assume because that makes this more interesting.)

Noting the reduced gravity and no frictional losses due to moving through air, the bullet would go a LONG way. Depending on the direction in which you fired it, it may not ever stop until it hit another object (in which case it may ricochet and continue going indefinitely), it may end up orbiting the moon, it may end up eventually in the ground on the moon if the angle is low enough for gravity to defeat the inertia of the bullet, it may go off into space and never stop, or it may end up caught in the earth's gravity and burning up in the earth's atmosphere.

Kind of an interesting thought.

Escape velocity on the surface of the moon is almost 8,000 ft/sec, and I am not aware of any handgun that comes close to that. Acceleration due to gravity on the moon is about 1.6 m/s so if you shot the gun from a height of 1.6 meters perpendicular to the ground it would take one second for it to impact the ground in a level area. Since it is essentially a vacuum, there would be negligible loses due to air resistance and it would then travel very close to the muzzle velocity times 1 sec: for .45 ACP that would be close to 1,000 feet.

As to ricocheting, the vacuum would not change the fact that the bullet and the ground would deform on impact absorbing most of the kinetic energy of the bullet.

txmatt wrote:

mr.72 wrote: Sure you will. Physics work the same. It's not like being under water where you have a viscous material preventing your mobility. As long as your center of gravity is distributed between your feet the same as it is here you are just as "firmly planted".

That seems correct assuming the muzzle velocity is the same, which it would probably be pretty close assuming the cartridge holding air thing worked (which we will assume because that makes this more interesting.)

Noting the reduced gravity and no frictional losses due to moving through air, the bullet would go a LONG way. Depending on the direction in which you fired it, it may not ever stop until it hit another object (in which case it may ricochet and continue going indefinitely), it may end up orbiting the moon, it may end up eventually in the ground on the moon if the angle is low enough for gravity to defeat the inertia of the bullet, it may go off into space and never stop, or it may end up caught in the earth's gravity and burning up in the earth's atmosphere.

Kind of an interesting thought.

Escape velocity on the surface of the moon is almost 8,000 ft/sec, and I am not aware of any handgun that comes close to that. Acceleration due to gravity on the moon is about 1.6 m/s so if you shot the gun from a height of 1.6 meters perpendicular to the ground it would take one second for it to impact the ground in a level area. Since it is essentially a vacuum, there would be negligible loses due to air resistance and it would then travel very close to the muzzle velocity times 1 sec: for .45 ACP that would be close to 1,000 feet.

As to ricocheting, the vacuum would not change the fact that the bullet and the ground would deform on impact absorbing most of the kinetic energy of the bullet.

Man, this forum has a bunch of geeks on it. I LOVE it!!!

The cartridge doesn't need it's own air or atmosphere. Solid propellants, including gun powder, contain their own oxygen.

I am sure the recoil would feel different because you are "lighter" in terms of weight but the recoil would not likely knock you over unless you were shoulder-firing a 10 gauge shotgun or something like that.

As KBCraig pointed out it is the mass, not the weight that is the determining factor of recoil. The shooter's mass and the mass of the gun and bullet are the same on the moon as on earth.

Gun powder has an oxidizer in it, no air required, but I would recommend a semi-auto as the pressure lost between the chamber and forcing cone on a revolver should cause a revolver to suffer from more reduced velocity than a semi auto. A semi-auto would need a stronger recoil spring in order to work properly as there is no air resistance. Speaking of the "lack of air resistance" you will see some, albeit minor, increased recoil due to that aspect.

txmatt wrote: Escape velocity on the surface of the moon is almost 8,000 ft/sec,

Well that settles it.

I didn't know that piece of data and didn't bother to look it up. So if you fire it parallel (well, tangent) to the surface of the moon, then the bullet will land on the ground. If you fire it straight up into the sky, then it will come back down on your head at the same velocity as that which it was fired.

G.A. Heath wrote:A semi-auto would need a stronger recoil spring in order to work properly as there is no air resistance. Speaking of the "lack of air resistance" you will see some, albeit minor, increased recoil due to that aspect.

I don't think air resistance would have anything to do with the recoil spring.
Recoil is a function of mass and acceleration.