PDA

View Full Version : Question for raaaid!



Bartsimpson-
03-21-2006, 06:16 AM
Raaaid question for you > if you stood on the surface moon and you fired a single shot from a high powered rifle where would the bullet end up ? .

Get it right and i'll award you with an apple

Bartman .

DaimonSyrius
03-21-2006, 06:18 AM
Originally posted by Bartsimpson-:
Get it right and i'll award you with an apple
Would that be Newton's apple perhaps? http://forums.ubi.com/images/smilies/16x16_smiley-tongue.gif

Cheers,
S.

P.S.: BTW, in the context of being on the Moon shooting around, you should specify how much power does 'high powered' mean http://forums.ubi.com/images/smilies/16x16_smiley-wink.gif

Dean3238
03-21-2006, 06:27 AM
Raaaid question for you > if you stood on the surface moon and you fired a single shot from a high powered rifle where would the bullet end up ? .

He'll need the rifle's muzzle velocity and angle of launch to get it right... ;-)

Dean

Wild.Bill.Kelso
03-21-2006, 06:35 AM
Originally posted by Bartsimpson-:
Raaaid question for you > if you stood on the surface moon and you fired a single shot from a high powered rifle where would the bullet end up ? .

Get it right and i'll award you with an apple

Bartman . This is a trick question! I think it depends greatly on where you point the rifle.

DaimonSyrius
03-21-2006, 06:38 AM
It depends completely on the two factors that Bartsimpson didn't tell, as it has been pointed out and Dean specified http://forums.ubi.com/images/smilies/16x16_smiley-happy.gif

Cheers,
S.

bogusheadbox
03-21-2006, 06:50 AM
????

Has it got anything to do with constant perpetual energy engines.

Or does it have something to do with eccentric bullets.

I think i will make a random post of fluid mechanics merged with quantum physics and parralel universes, just to see how long my cats hair will grow when its strapped to my wing flying at 400 mph at 125.43 degrees, constant level, at 4.13 pm.

Wild.Bill.Kelso
03-21-2006, 07:07 AM
Won't he need to know how much gravity there is on the Moon?

Max.Power
03-21-2006, 07:30 AM
I don't think that you need to know anything else. I think I have the answer but I don't want to spoil it.

Dean3238
03-21-2006, 08:18 AM
Won't he need to know how much gravity there is on the Moon?


Sure, but constants are easy to look up. Launch variables must be specified in the problem.

Dean

DaimonSyrius
03-21-2006, 08:33 AM
Something else should be better specified about the 'high powered rifle' itself, maybe about the astronaut gear of the shooter.

http://forums.ubi.com/images/smilies/16x16_smiley-happy.gif

S.

Dean3238
03-21-2006, 09:03 AM
Something else should be better specified about the 'high powered rifle' itself, maybe about the astronaut gear of the shooter.

Well, depending on how hard you want to press this, details on the ability of the astro-shooter to keep recoil to a minimum (and just how much energy is lost due to it) and some data on how rifle propellants 'fire' in a vacuum. But then, how accurate are we trying to be anyway? :-)

This is a discussion about perpetual motion machines and such, after all.

Dean

raaaid
03-21-2006, 10:22 AM
if you neglect the posibility of the bullet hitting the surface of the moon the bullet can return to you or reach escape velocity

if escape velocity is reached according to nasa it will make an hiperbolic trajectory

according to my logic it will make a geometric squared spiral trajectory because gravity reduces to the square of the distance so the change of direction of the spiral will also reduce with the distance to the center(so you get a spiral which tends to go the same direction than the radius but spirals turn forever), it will tend to make an infinite circle with a trajectory normal to the radius(spirals are fun)

escape velocity is very interesting because it deals with infinity so i have the right to think nasa and newton are wrong and is not that i believe i just think by myself

the bullet is one km away and gravity changes it course 1º,when its two km away it will change 0,25º , at 4km it will be 1/16º, as the distance tends to infinite the change of trajectory tends to 0

if the change of course tends to 0 the trajectroy tends to be straight(an hiperbole) but we are dealing with infinity and a squared spiral tend to a straigh line also but infinity makes them turn forever

it can be the nasa- newton way or the geometrical way in wich spirals in the infinite are a circle of infinite radius and a straight line at the same time becaus the change of direction tend to 0

im just supsicious im not being told the whole truth, i wouldnt put the hand on fire

of course in the zenon turtle you never reach destination but in my opinion infinite is never reached so gravity will never be 0 so the change of course cant be 0 being an hiperbolic trajectory but there will be a change of course that tends to 0 although it never gets straight just as spirals

therefore the bullet if escape velocity is reached will go in an infinite spiral not in an hiperbolic trajectory, i base my opinion in the fact that infinte by definition of it is something that can be reached otherwise is not infinite so gravity is never 0, the bullet will turn forever around you but youll never see it again http://forums.ubi.com/images/smilies/16x16_smiley-sad.gif

DaimonSyrius
03-21-2006, 10:28 AM
Originally posted by Dean3238:
some data on how rifle propellants 'fire' in a vacuum
OK, we can speak openly now that raaid has placed his bet. I was thinking about how the 'high powered rifle' actually powers the bullets in the first place, of course... electric power? nuclear? It shouldn't just be gunpowder in the round... or else the bullet should end up within the gun where it was to begin with http://forums.ubi.com/images/smilies/16x16_smiley-happy.gif

Cheers,
S.

CPS_Triad
03-21-2006, 10:32 AM
I have a different take on this: provided that we are talking about high powered rifles in our commonly understood sense, with lead slug, metal jacket, and gunpowder propellant, I would speculate that the slug would end up on the moon's surface, probably not far from where it was fired.

My reasoning: stardard ammunition needs oxygen to burn; while there may be 'air' trapped inside the propellant area, it wouldn't be enough to seperate the projectile from the propellent load- which may produce a fizzle, at best.

That's my opinion and I am sticking with it http://forums.ubi.com/groupee_common/emoticons/icon_cool.gif

What do you all think?

Triad

Dean3238
03-21-2006, 10:44 AM
My reasoning: stardard ammunition needs oxygen to burn; while there may be 'air' trapped inside the propellant area, it wouldn't be enough to seperate the projectile from the propellent load- which may produce a fizzle, at best.


Depends on the seal of the cartidge and how long it has been exposed to a vacuum. Then it will matter if you have enough oxygen left in there to support even minor combustion. I suppose it might be possible to encase the round on earth with a substance that will keep the enclosed atmosphere from leaking (too fast?) in a vacuum, yet will separate when the firing occurs (think dipped in wax, only better...)...

In theory, if you could retain enough oxygen in the round you could get it to fire at some percentage of earth capabilities.

Couldn't our astronaut be armed with a death ray or something? Might be simpler. http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

Dean

Dean3238
03-21-2006, 10:47 AM
Of course, if our astronaut is _really_ slick, he could fire the weapon such that the round's orbit will intersect the node it was fired from after it goes around the moon.

Thereby allowing said astronaut to shoot himself in the head while aiming away from his body. http://forums.ubi.com/images/smilies/88.gif

DaimonSyrius
03-21-2006, 10:50 AM
Originally posted by Dean3238:
Of course, if our astronaut is _really_ slick, he could fire the weapon such that the round's orbit will intersect the node it was fired from after it goes around the moon.

Thereby allowing said astronaut to shoot himself in the head while aiming away from his body. http://forums.ubi.com/images/smilies/88.gif
Along that same reasoning, the astronaut could just reverse the rifle in the horizontal plane and let the bullet get back into the barrel to end the trip safely in. Wouldn't that be even cooler than slick? http://forums.ubi.com/groupee_common/emoticons/icon_razz.gif

All it would take would be a mere perfect accuracy in every movement.

Or we could just neglect everything and just imagine whatever we want http://forums.ubi.com/images/smilies/16x16_smiley-very-happy.gif http://forums.ubi.com/images/smilies/16x16_smiley-very-happy.gif

Cheers,
S.

Dean3238
03-21-2006, 11:02 AM
All it would take would be a mere perfect accuracy in every movement.

Yup, He'd do better to turn around, put on a catcher's mitt and take up his best Johnny Bench stance.

Just don't tell him that sans atmosphere, the bullet will be still travelling at its muzzle velocity when it his the mitt, goes through his hand into his chest.

Reality bites. No wonder so many refuse to believe in it. http://forums.ubi.com/images/smilies/53.gif

Dean

DaimonSyrius
03-21-2006, 11:07 AM
Originally posted by Dean3238:
Reality bites. No wonder so many refuse to believe in it. http://forums.ubi.com/images/smilies/53.gif
I can't believe I'm posting in this thread while not being sure whether it's this one or the other one http://forums.ubi.com/images/smilies/88.gif

Cheers,
S.

Kocur_
03-21-2006, 11:35 AM
Propellants consist oxidant dont you think http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif Guns work normally in space (apart from cold). Soviets fired 23mm cannon in space from a military "spy" station.

DaimonSyrius
03-21-2006, 11:48 AM
Originally posted by Kocur_:
Soviets fired 23mm cannon in space from a military "spy" station.
Did they? There's apparently no end to what soviets can do http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

And where did the shells end up? http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

Cheers,
S.

Kocur_
03-21-2006, 11:57 AM
Only for defence, as always http://forums.ubi.com/images/smilies/winky.gif

Where they end up? Silly question. On target naturally!!! http://forums.ubi.com/images/smilies/16x16_smiley-very-happy.gif

http://en.wikipedia.org/wiki/Salyut

Waldo.Pepper
03-21-2006, 12:46 PM
Originally posted by Kocur_:
Only for defence, as always http://forums.ubi.com/images/smilies/winky.gif

Where they end up? Silly question. On target naturally!!! http://forums.ubi.com/images/smilies/16x16_smiley-very-happy.gif

http://en.wikipedia.org/wiki/Salyut

Thanks. Learn something new everyday.

MonkeyHero
03-21-2006, 12:57 PM
I was personally under the impression that there was no oxygen on the moon.

Dean3238
03-21-2006, 01:06 PM
Soviets fired 23mm cannon in space from a military "spy" station.


Orbital version of CWIZ (SP?)? ("Christ, it WON'T Shoot!!!"). Never know when your space station needs a point defense against, say, Martian Kamakazie missions (feindish Green devils).

Dean

Dean3238
03-21-2006, 01:09 PM
I was personally under the impression that there was no oxygen on the moon.

You just have to really stomp on the green-cheese hard hard to get it to leak out... http://forums.ubi.com/images/smilies/metal.gif

Dean

Dean3238
03-21-2006, 01:38 PM
Wow.

Thirty years ago with a piece of graph paper and simple 2-D vectors we made a game out of planning orbits, escape velocities and so forth. Diversion for HS physics students.

It isn't rocket science... even in this context.

I'm simply staggered at what I just read. http://forums.ubi.com/images/smilies/16x16_smiley-surprised.gif

Dean

Dean3238
03-21-2006, 02:03 PM
OK... I'll tilt at the windmill...once


if you neglect the posibility of the bullet hitting the surface of the moon the bullet can return to you or reach escape velocity

This is why muzzle velocity and angle of launch is critical. If the wrong combination is input, you either crash downrange somewhere, or go zipping into space forever.


if escape velocity is reached according to nasa it will make an hiperbolic trajectory

"Hyperbolic", but yes. I'd advise checking the definition of such a curve, which has your distance and force effects built-in. Executive Summary: A curve that does not come back on itself. This is how you use some planet, like Jupiter, to speed up your spacecraft to get further into the solar system faster. It also defines the flight paths of comets that zip into the inner solar system and then race out into space never to be seen again. As opposed to an elliptical, or circular path, where the object falls in and repeats.


according to my logic it will make a geometric squared spiral trajectory because gravity reduces to the square of the distance so the change of direction of the spiral will also reduce with the distance to the center(so you get a spiral which tends to go the same direction than the radius but spirals turn forever), it will tend to make an infinite circle with a trajectory normal to the radius(spirals are fun)

Depends on the speed involved. If you are slow enough, gravity will, eventually, pull you back around the object making the field. But that's a pretty sloppy way to do buisness in spaceflight (not a good thing if your crew will come back... 1,000 years from now). Go too slow and you'll plow into the ground downrange (you can produce that effect with a rock every day of the week). Go "just right" and you go into a predictable orbit. Too fast and the thing will not close on itself (check the directions of your 'course change' vectors as the object gets further away, they are no longer just shifting course, they are angled back toward the dense object, theoretically slowing you ever so slightly.)

Anyway, most 'escape velocities' are merely speeds that allow you to move futher away from the dense body. Most spacecraft don't _need_ to escape forever, only enough to do their mission. Apollo needed enough velocity to change from earth orbital paths to lunar orbital paths. Without a moon, the Apollo speed would merely be a long, ugly Earth orbit.

Not sure what any of this has to do with IL2, but hope it made some sense to you. http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

Dean

NonWonderDog
03-21-2006, 02:26 PM
Propellants don't need outside oxygen to burn (there are oxidizers in the cartridge -- guns wouldn't even fire in Earth atmosphere otherwise), so the bullet would fire normally and enter an orbit. The orbit might be elliptical, parabolic, or hyperbolic, and it might intersect the surface of the moon, depending on launch parameters.

Basically the bullet would either hit the moon or escape into an orbit about Earth unless you fired it parallel to the surface of the moon at a velocity between circular velcity and escape velocity -- in which case you have a slim chance to be dead in a few minutes. http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

What was the point of this question?

DaimonSyrius
03-21-2006, 02:31 PM
Originally posted by Kocur_:
Where they end up? Silly question.
It is indeed http://forums.ubi.com/images/smilies/16x16_smiley-very-happy.gif but it happens to be the original poster's question http://forums.ubi.com/groupee_common/emoticons/icon_razz.gif

Good point by Kocur, so it's back to square one, or square two, rather... Shooting vector is needed to know where the bullet might end up (or end down, as it may be the case http://forums.ubi.com/groupee_common/emoticons/icon_razz.gif)

http://forums.ubi.com/images/smilies/16x16_smiley-happy.gif

Cheers,
S.

Kocur_
03-21-2006, 03:44 PM
In fact what I said wasnt related to original question, but to firing at quite close object in Earth's orbit - so my case was much easier http://forums.ubi.com/groupee_common/emoticons/icon_wink.gif

Max.Power
03-21-2006, 04:03 PM
My answer:

Given the amount of information given in the question and the assumption that it is possible for the purposes of the excercise:

The bullet would end up on the surface of the moon.

Dean3238
03-21-2006, 04:15 PM
The bullet would end up on the surface of the moon.

"Inside", "next to", or "in front" of the astronaut?

That's the question the peanut gallery wants to know the answer to... http://forums.ubi.com/images/smilies/winky.gif

Dean

DaimonSyrius
03-21-2006, 06:51 PM
*Calling BartSimpson*

Velocity vector on firing the 'high powered rifle* is needed to solve the problem...

*Ground Control to Major Tom*
*This is Major Tom to Ground Control*

http://forums.ubi.com/images/smilies/16x16_smiley-happy.gif

Cheers,

Akronnick
03-21-2006, 08:44 PM
The bullet would lodge itself in the astronauts boot. http://forums.ubi.com/images/smilies/784.gif

*I'm stepping through the door*
*And I'm floating in a most peculiar way*
*And the stars look very different TODAY!!*

Zeus-cat
03-21-2006, 09:01 PM
If the astronaut was Barney Fife, the bullet would still be in his shirt pocket.

Max.Power
03-21-2006, 10:50 PM
I think that all this calling for more information is falling into the trap that the original poster set. You make it more complicated than it needs to be... like raaaid makes his posts.

NonWonderDog
03-21-2006, 11:02 PM
No... the question just has no specific answer without more information. The resultant orbit depends 100% on the speed and direction of the bullet.

Akronnick
03-22-2006, 01:15 AM
Ok, for the sake of argument, let's asume that the bullet was fired due East. (with East corresponding your right if you are facing the Moon's North Pole, which is on the end of the Moon facing the star Polaris.) Furthermore, let us assume the rifle is a .30-06 Springfield (http://en.wikipedia.org/wiki/.30-06_Springfield#Performance) firing ball M2 ammo with a muzzle velocity of 835m/s.
And finally, the rifle is aimed parallel to the surface of the Moon, being mounted on a stand so that the rifle is 1.5 meters above the Lunar ground.

and Now the Question: Where, if anywhere, will the bullet land?

And now the Physics:

The acceleration of gravity at the surface of the Moon (http://en.wikipedia.org/wiki/Moon) is 1.622m/s^2, knowing this how long will the bullet fly before it hits the ground?

the answer is 1.56 s.

now, how far downrange will the bullet travel during that time?

the answer is 1.56s*835m/s= aproxiamtely 1.33Km down range.

xTHRUDx
03-22-2006, 01:17 AM
here guys, play with some gravity:
http://www.colorado.edu/physics/2000/applets/satellites.html
click anywhere in the black, drag a bit and let go.

Akronnick
03-22-2006, 01:26 AM
And if anyone's interested, escape velocity from the Moon is 2.38km/s.

Bartsimpson-
03-22-2006, 03:57 AM
Ok here is the answer , are we all ready !! .

Taking in to account as we all know the moon is void of any atmosphere and therefore no resistance and as we also know the moon has a very limited amount of it's own gravity , so a bullet fired from a given high powered rifle the trajectory of the bullet would take the path of the circumference of the moon and ultimately following it's own trajectory path which would mean a complete orbit , so a complete orbit by the bullet with no deviation would end up where it started which would mean the bullet ending up in the back of your head ! that is of coarse if you happen to stand in the same position as your initial firing of the rifle .

The moral to the story is don't take up shooting if you ever make it to the moon one day .

Bartman .

DaimonSyrius
03-22-2006, 04:20 AM
Disappointing, Bartsimpson. http://forums.ubi.com/images/smilies/disagree.gif http://forums.ubi.com/images/smilies/16x16_smiley-happy.gif

You're neglecting (in a similar way to how raiid often builds his arguments) that whether the 'high powered' bullet will or won't stabilise in some orbit will depend on its initial speed and angle, that is, the velocity vector. Does your 'high powered' bullet have a muzzle velocity greater or lower than the escape velocity for the Moon?

You're neglecting also to consider how the actual height of an (eventually established) orbit will depend also on the same factors (think parabolas, hyperbolas, spirals and ellipses here, not just simply circles).

So, no apple for you. If it was Newton's apple, you never had it to start with, so you could not award it to raaid nor to anyone else. http://forums.ubi.com/images/smilies/16x16_smiley-very-happy.gif

Cheers,
S.

P.S.: Apparently, you've failed also to read the thread you started before providing your 'answer'. That's even more disappointing http://forums.ubi.com/images/smilies/disagree.gif http://forums.ubi.com/images/smilies/16x16_smiley-happy.gif

Still, it was fun http://forums.ubi.com/images/smilies/16x16_smiley-happy.gif

I liked the whole 'Space Oddity' aspect of it http://forums.ubi.com/images/smilies/16x16_smiley-wink.gif

Dean3238
03-22-2006, 05:53 AM
If the astronaut was Barney Fife, the bullet would still be in his shirt pocket.

This could be troublesome if the shirt is worn under his pressure suit...

Gotta be careful who we send to the moon to test this gun theory. You want a moron, true, but the _right_ kind of moron.

Dean

Dean3238
03-22-2006, 06:01 AM
here guys, play with some gravity:
http://www.colorado.edu/physics/2000/applets/satellites.html

Now _that's_ a cool little toy! Good job.

Dean

raaaid
03-22-2006, 07:16 AM
amazing toy

if you put a satellite into orbit youll notice it will make an ellipse composed of an inwards and outwards spiral

the inwards spiral propells the nucleus with more force than the outwards one,being inwards and outwards spirals in different halfs the nucleus is propelled towards the inner spiral

youll probably say no both inwards and outwards spirals pull the same then answer me this question what would you prefer hold a cannonball with a spool giving away cable or having to recover the cannonball in an inwards spiral? i have strength to hold the spool in an outwards spiral but have no strengt to make an inwards one

Dean3238
03-22-2006, 07:43 AM
if you put a satellite into orbit youll notice it will make an ellipse composed of an inwards and outwards spiral

I have no idea what you mean by this "spiral" stuff... You have a velocity vector and an acceleration (delta). The velocity vector is dead on your flight path of whatever magnitude it happens to be. Barring any outside forces, it will never change either magnitude or direction (thank you, Dr. Newton).

The acceleration is the force of gravity. Strength based on the mass involved and the distance, direction toward the center of mass of both bodies.

Two object, simple frictionless mechanics, it don't get no simpler than that...

Dean

DaimonSyrius
03-22-2006, 07:57 AM
Originally posted by raaaid:
youll probably say no both inwards and outwards spirals pull the same then answer me this question what would you prefer hold a cannonball with a spool giving away cable or having to recover the cannonball in an inwards spiral? i have strength to hold the spool in an outwards spiral but have no strengt to make an inwards one
Doesn't that question about cannonballs belong into your own thread about the subject, raaid? http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif
I know this thread is about a question posed to you, but it wasn't that question... while in your thread about 'antigravity for kids', you were asking precisely that question http://forums.ubi.com/images/smilies/16x16_smiley-happy.gif

Sounds confusing? Well, it is, a lot http://forums.ubi.com/images/smilies/16x16_smiley-very-happy.gif
That's why I'm suggesting that you keep questions and thoughts well arranged, and maybe then it might become less confusing http://forums.ubi.com/images/smilies/16x16_smiley-happy.gif

Cheers,
S.

DaimonSyrius
03-22-2006, 08:04 AM
Originally posted by Dean3238:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content"> if you put a satellite into orbit youll notice it will make an ellipse composed of an inwards and outwards spiral

I have no idea what you mean by this "spiral" stuff... </div></BLOCKQUOTE>
I would say that raaid's correct here, if you take it to mean that you can look at different segments of an elliptic orbit this way: the radius of curvature decreases as the orbit approaches one focus of the ellipse ("inwards spiral" part, in raiid's words) to a minimum value; and then the radius of curvature increases to form the 'flatter' segment of the ellipse as it goes away from that focus ("outwards spiral" part) to a maximum radius of curvature value, half-way in that 'flatter' segment. This will repeat at the other focus, of course.

Now, the 'nucleus' parts, and the cannon balls, spool, cables, and especially antigravity as an outcome of all the above; those remain completely and utterly unclear to me too http://forums.ubi.com/images/smilies/16x16_smiley-wink.gif

Cheers,
S.

Dean3238
03-22-2006, 08:15 AM
I would say that raaid's correct here, if you take it to mean that you can look at different segments of an elliptic orbit this way: the radius of curvature decreases as the orbit approaches one focus of the ellipse ("inwards spiral" part, in raiid's words); and then the radius of curvature increases to form the 'flatter' segment of the ellipse as it goes away from that focus ("outwards spiral" part). This will repeat at the other focus, of course.

I'll work with that as a description of the eventual flight path, do you suppose he "gets" why all this going on (the vectors involved)?

Since the resultants created by the velocity vector and applied forces _creates_ the various modes he sees as a 'conspiracy of lies' (circular, elliptical, 'hiperbolic' escape paths), getting him to understand the basic vector addition is key.

Yeah, I'm confused...

Dean

DaimonSyrius
03-22-2006, 08:20 AM
Originally posted by Dean3238:
I'll work with that as a description of the eventual flight path, do you suppose he "gets" why all this going on (the vectors involved)?
(I was still editing my post, sorry, I think it's better worded now)

I'm unable to make any guess at all about how raaid's mind works http://forums.ubi.com/images/smilies/16x16_smiley-happy.gif


Yeah, I'm confused...
Yep, same here... that's why only raaid could explain, and then he doesn't http://forums.ubi.com/images/smilies/16x16_smiley-happy.gif
*Edit* I must add here that raaid's ideas, while confusing (and very possibly confused themselves, in my view), have this particular something that confers to them the property of being nice primers for discussions about all sorts of things.

Cheers,
S.

Dean3238
03-22-2006, 08:36 AM
I'm unable to make any guess at all about how raaid's mind works...

Err... was this the same fellow with the thread a while back claiming lift was "money for nothing"?

Alternative universe physics is a pain... Rules? We don't need no stink'in rules!

Dean

bigchump
03-22-2006, 09:21 AM
Will I have to change my convergence when we get the moon map?

Dean3238
03-22-2006, 09:52 AM
Will I have to change my convergence when we get the moon map?

Depends, did they get dirty?

http://forums.ubi.com/groupee_common/emoticons/icon_biggrin.gif

Dean

NonWonderDog
03-22-2006, 10:13 AM
Forget the spiral stuff, it's a ******* ellipse. A *perfect* ellipse, that fits the formula for an ellipse *perfectly.* (Unless the bullet is fired at or above escape velocity.)

Remember high-school geometry? There are two foci, one of them is the moon. The other is empty. The aggregate distance between each focus and any point on the orbit is constant.


The bullet would not hit you in the back of the head because, among other things, the moon rotates on its axis at a rate of 1 rev/28 days or so. That should be fast enough to move three inches during an orbit. (maybe not, but it's not worth the calculation) The rifle probably wouldn't be able to fire the round at circular velocity anyway, so it would just hit the surface of the moon somewhere downrange. Assuming it DID have enough speed to make a circular orbit, it would have to be perfectly aimed at the precise inclination in order for you to hit yourself, and no rifle can fire tight enough a grouping to do that.

The chances of hitting yourself within a few orbits would be less than winning the lottery. If you stand in the same place for a year the odds are a bit better.

Z4K
03-23-2006, 03:27 AM
Originally posted by Bartsimpson-:
...and as we also know the moon has a very limited amount of it's own gravity.

Gee. Any astronauts planning to return had better get in quick before it all runs out... Otherwise they'll need to nail the lander down so it won't float away.