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imachavel
I loved and lost but I loved-ftw



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Re: so in theory in space....... [Re: DieCommie]
#14879749 - 08/06/11 02:37 AM (12 years, 9 months ago) |
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Quote:
DieCommie said: I would guess that grenades already do have the oxygen in the fuel. 
Im not sure it would combust fast enough if it didnt.
well speed isn't what I'm thinking of, any explosive can com bust as fast as it wants, look at c4. I think what you mean is if the fuse wasn't sealed but the inside explosive was then how would it get oxygen to com bust?
mainly I'm just thinking that when a fuse is pulled on a grenade, you don't see smoke. therefore the fuse and entire reaction must be self contained, am I wrong?
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I did not say to edit my signature soulidarity! Now forever I will never remember what I said about understanding the secrets of the universe by paying attention to subtleties!
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ChuangTzu
starvingphysicist



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Re: so in theory in space....... [Re: imachavel]
#14881779 - 08/06/11 04:37 PM (12 years, 9 months ago) |
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Grenades are (or at least should be) completely sealed up for the most part. This prevents them from being rendered inoperable if submerged in water. The entire process of detonation of a grenade is self-contained. You could even put the grenade under water, pull the pin, release the spoon, and it would detonate.
Even old-school cannon fuse will burn under water.
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Seuss
Error: divide byzero



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Re: so in theory in space....... [Re: ChuangTzu]
#14882155 - 08/06/11 06:11 PM (12 years, 9 months ago) |
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The US grenades are much simpler than the picture above. The fuse assembly (M213) contains the striker, striker spring, primer (percussion cap), delay train (chemical delay), and detonator all in line with one another. The delay train is specified by mil-c-13789a (good luck finding a copy), and is required to burn in an enclosed environment (no access to external oxygen). Most compositions use potassium nitrate, potassium chlorate, or potassium perchlorate as an oxidizer along with something to consume the oxygen (charcoal) and a binder (dextrin) to regulate burning speed. The donator is several layers, typically lead styphnate followed by lead azide followed by PETN. *sigh* Sometimes, I miss my old job...
-------------------- Just another spore in the wind.
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ChuangTzu
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Re: so in theory in space....... [Re: Seuss]
#14882259 - 08/06/11 06:32 PM (12 years, 9 months ago) |
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Quote:
Seuss said: The US grenades are much simpler than the picture above.
Yeah. On those, the assembly you mention is part of the same mechanism that contains the lever, pin, and everything else except the case and main explosive charge. It all screws in from the top and there are no other holes in the case.
Quote:
*sigh* Sometimes, I miss my old job...
I wish that was my job. I got a demilled Mk.II grenade when I was a kid and spent hours disassembling it and putting it back together again. If I remember right, there were only 3 or 4 pieces but I was fascinated nonetheless.
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Jryan
The Thinker


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Re: so in theory in space....... [Re: ChuangTzu]
#14882353 - 08/06/11 06:57 PM (12 years, 9 months ago) |
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First of all, chemical reactions do not require oxygen to detonate (From what I can remember about fire safety, this is why you can't poor water on a chemical fire to put it out). Second of all, we can just look at our favorite person of all times, NEWTON. An object in motion will remain in motion, unless acted upon by another force. Also, every action has an equal and opposite reaction. So what ever happened to the grenade, would also happen to the spaceship. BUT, lets not forget that the spaceship's mass is WAY more than the grenades, hehe, now we are going to have a debate. Trust me when I say, that both objects would move away from each other at the same rate.
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DieCommie

Registered: 12/11/03
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Re: so in theory in space....... [Re: Jryan]
#14882366 - 08/06/11 07:00 PM (12 years, 9 months ago) |
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Quote:
First of all, chemical reactions do not require oxygen to detonate (From what I can remember about fire safety, this is why you can't poor water on a chemical fire to put it out).
Combustion reactions do, and thats what happens in a grenade.
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Jryan
The Thinker


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Re: so in theory in space....... [Re: DieCommie]
#14882378 - 08/06/11 07:05 PM (12 years, 9 months ago) |
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Quote:
ChuangTzu said:
Quote:
Seuss said: The US grenades are much simpler than the picture above.
Yeah. On those, the assembly you mention is part of the same mechanism that contains the lever, pin, and everything else except the case and main explosive charge. It all screws in from the top and there are no other holes in the case.
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*sigh* Sometimes, I miss my old job...
I wish that was my job. I got a demilled Mk.II grenade when I was a kid and spent hours disassembling it and putting it back together again. If I remember right, there were only 3 or 4 pieces but I was fascinated nonetheless.
Quote:
DieCommie said:
Quote:
First of all, chemical reactions do not require oxygen to detonate (From what I can remember about fire safety, this is why you can't poor water on a chemical fire to put it out).
Combustion reactions do, and thats what happens in a grenade.
Ah, are you referring to the fuse then?
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DieCommie

Registered: 12/11/03
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Re: so in theory in space....... [Re: Jryan]
#14882379 - 08/06/11 07:06 PM (12 years, 9 months ago) |
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No, Im referring to the final detonation.
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Jryan
The Thinker


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Re: so in theory in space....... [Re: DieCommie]
#14882388 - 08/06/11 07:08 PM (12 years, 9 months ago) |
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Quote:
DieCommie said: No, Im referring to the final detonation.
So maybe it is a "space Granade" ;-0
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ChuangTzu
starvingphysicist



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Re: so in theory in space....... [Re: Jryan]
#14882448 - 08/06/11 07:23 PM (12 years, 9 months ago) |
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If explosives relied on atmospheric oxygen, their burn rate would be severely limited and they wouldn't do much exploding. That is why every explosive and propellant ever used packs its own oxidizer, whether it's contained with fuel in the same molecule, or separately as a mixture.
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Jryan
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Re: so in theory in space....... [Re: ChuangTzu]
#14882456 - 08/06/11 07:25 PM (12 years, 9 months ago) |
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Quote:
ChuangTzu said: If explosives relied on atmospheric oxygen, their burn rate would be severely limited and they wouldn't do much exploding. That is why every explosive and propellant ever used packs its own oxidizer, whether it's contained with fuel in the same molecule, or separately as a mixture.
But, if their was any explosion AT all, both objects (Granades matter and Spaceships matter) would move in the opposite directions at the same rate. Newtonian physics ftw!
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ChuangTzu
starvingphysicist



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Re: so in theory in space....... [Re: Jryan]
#14882502 - 08/06/11 07:35 PM (12 years, 9 months ago) |
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Jryan said: But, if their was any explosion AT all, both objects (Granades matter and Spaceships matter) would move in the opposite directions at the same rate. Newtonian physics ftw!
Not exactly.
The grenade's momentum would be conserved, sending shrapnel out radially in such a pattern that the average momentum of the pieces of the grenade is the same as the grenade had before the explosion.
The momentum of the grenade + spaceship system would remain the same too. Any particles of the exploding grenade that impinge on the space ship would transfer some momentum to it losing momentum. The space ship moves off in such a way that the average momentum remains the same.
The grenade ceases to be an object per se when it blows up and becomes a massive number of particles of various masses and velocities. The key is that the momentum is conserved, not that the the pieces leave at the same rate. This would only be the case in certain, particular situations (for example, if the space ship and grenade were loaded into a tube, the grenade's propellant charge was placed between them, and the grenade and space ship had the same mass).
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imachavel
I loved and lost but I loved-ftw



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Re: so in theory in space....... [Re: ChuangTzu]
#14883712 - 08/07/11 01:03 AM (12 years, 9 months ago) |
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yes, I understand. I wish grim reaper did he seems to have a hard time understanding. if a grenades fuse wasn't self contained you would see some smoke, no such thing happens.
it is amazing that in space if no force acts upon the explosion, the particles, although scattered, will travel infinitely through space at the same speed until they hit something, minus the shock wave blast, as I believe that needs air to transfer. amazing stuff!
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I did not say to edit my signature soulidarity! Now forever I will never remember what I said about understanding the secrets of the universe by paying attention to subtleties!
I'm never giving you the password again. Jerk
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Jryan
The Thinker


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Re: so in theory in space....... [Re: ChuangTzu]
#14884984 - 08/07/11 10:53 AM (12 years, 9 months ago) |
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Quote:
ChuangTzu said:
Quote:
Jryan said: But, if their was any explosion AT all, both objects (Granades matter and Spaceships matter) would move in the opposite directions at the same rate. Newtonian physics ftw!
Not exactly.
The grenade's momentum would be conserved, sending shrapnel out radially in such a pattern that the average momentum of the pieces of the grenade is the same as the grenade had before the explosion.
The momentum of the grenade + spaceship system would remain the same too. Any particles of the exploding grenade that impinge on the space ship would transfer some momentum to it losing momentum. The space ship moves off in such a way that the average momentum remains the same.
The grenade ceases to be an object per se when it blows up and becomes a massive number of particles of various masses and velocities. The key is that the momentum is conserved, not that the the pieces leave at the same rate. This would only be the case in certain, particular situations (for example, if the space ship and grenade were loaded into a tube, the grenade's propellant charge was placed between them, and the grenade and space ship had the same mass).
Good explanation
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imachavel
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Re: so in theory in space....... [Re: Jryan]
#14886466 - 08/07/11 04:39 PM (12 years, 9 months ago) |
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yes, of course, momentum is conserved, but that doesn't mean the rules apply COMPLETELY differently just because the objects are in microgravity instead of on earth. if two freight trains slam into each other, will they both because of opposite reaction be pushed backwards in the opposite direction and keep traveling that way? definitely not. this is the difference with objects in space, obviously things don't work exactly the same. but will two freight trains somehow speeding towards each other in a straight line in space, once crashed into each other, both pummel backwards in a perfect direction at the exact same speed they crashed into each other? I think not. the reaction might be different then on earth, but not THAT different, the effect is the same.
now someone said don't even ask why, but that he knew for sure that a grenade exploding right next to the international space station would give both objects equal momentum, the space station, and the grenade shards. I know this isn't true, one thing being the space stations mass is much much greater. but he said this wouldn't matter. surely it would. Now would the space station gain momentum in the opposite direction from the reaction? surely, but it isn't conserved with completely different rules then the ones governing physics on earth. the reaction might be more exaggerated, but the greater mass will mean the space station will only gain so much momentum, as a reaction from the force acted upon it from the grenade.
imho I think it would be pretty impressive all together, just to see the grenade explode next to the international space station, and to see the space station start to move in the opposite direction from the force of the blast. in this example, if the gravity of earth didn't stop the space station, it also, would travel through space in the opposite direction at the same velocity it started moving when the grenade forced it in the opposite direction, for infinity. even slowly, this would be an amazing phenomenon. it's obvious this law holds true, as voyager didn't have it's rockets on towards it's entire trip towards Jupiter, just enough to get it hurtling through space, and then obviously it got momentum and changed trajectory sling shooting off other planets orbits.
the laws of physics in space can be well experienced by playing the game asteroids. the only thing people barely can account for are gravitons. but we know a bigger object with much larger mass and density will very much so attract a smaller object into orbit around it. we've seen it happen in experiments aboard the international space station. salt forms clumps and the smaller clumps will eventually start a slow orbit around the larger clumps after awhile. water itself will form a perfect sphere, showing gravitons are exerted by all objects no matter how small they are. of course this is INSIDE the international space station, where the pressure will keep the water from vaporizing.
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I did not say to edit my signature soulidarity! Now forever I will never remember what I said about understanding the secrets of the universe by paying attention to subtleties!
I'm never giving you the password again. Jerk
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ChuangTzu
starvingphysicist



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Re: so in theory in space....... [Re: imachavel]
#14888490 - 08/08/11 01:52 AM (12 years, 9 months ago) |
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Quote:
imachavel said: yes, of course, momentum is conserved, but that doesn't mean the rules apply COMPLETELY differently just because the objects are in microgravity instead of on earth. if two freight trains slam into each other, will they both because of opposite reaction be pushed backwards in the opposite direction and keep traveling that way? definitely not. this is the difference with objects in space, obviously things don't work exactly the same. but will two freight trains somehow speeding towards each other in a straight line in space, once crashed into each other, both pummel backwards in a perfect direction at the exact same speed they crashed into each other? I think not. the reaction might be different then on earth, but not THAT different, the effect is the same.
There is no distinction between trains crashing in space or trains crashing on Earth. A train collision is an inelastic collision because of all the metal that gets fucked up in the process of the crash, which dumps energy to heat.
Quote:
now someone said don't even ask why, but that he knew for sure that a grenade exploding right next to the international space station would give both objects equal momentum, the space station, and the grenade shards. I know this isn't true, one thing being the space stations mass is much much greater. but he said this wouldn't matter. surely it would. Now would the space station gain momentum in the opposite direction from the reaction? surely, but it isn't conserved with completely different rules then the ones governing physics on earth. the reaction might be more exaggerated, but the greater mass will mean the space station will only gain so much momentum, as a reaction from the force acted upon it from the grenade.
Momentum is conserved. This doesn't mean that it is partitioned equally between the grenade and space station--whether this happens in space or on Earth. This is because of the different cross sections of reaction of grenade casing and space station with the actual explosion. Conservation of momentum doesn't require equal momenta for everything involved in the reaction, just that the average momentum of the system remains the same.
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water itself will form a perfect sphere, showing gravitons are exerted by all objects no matter how small they are.
This is because of the surface tension of water, not because of its gravity.
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myc0nob
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Re: so in theory in space....... [Re: ChuangTzu]
#14899992 - 08/10/11 07:30 AM (12 years, 9 months ago) |
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no, it'd not, you don't consider that when the expansion stops, it'll gauss out, also, the gasses will cool down and compact.
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ChuangTzu
starvingphysicist



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Re: so in theory in space....... [Re: myc0nob]
#14900702 - 08/10/11 11:28 AM (12 years, 9 months ago) |
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myc0nob said: no, it'd not, you don't consider that when the expansion stops, it'll gauss out, also, the gasses will cool down and compact.
Did you mean to respond to me, or was that for someone else?
Try using the quote function to make it more clear what point you are addressing.
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imachavel
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Re: so in theory in space....... [Re: ChuangTzu]
#14904989 - 08/11/11 05:52 AM (12 years, 9 months ago) |
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Quote:
ChuangTzu said:
This is because of the surface tension of water, not because of its gravity.
then why would it form a perfect sphere? the surface tension could hold it together relatively easy without it having to form a perfect sphere, it could be ovoid, or geometrical, and still hold together. it forms a perfectly balanced sphere. and if you leave the water spread out as drops the drops will eventually crash into each other and form a perfect sphere. this is what mercury does on earth. do they really crash or are they attracted to each other? why would you think that gravity only exists on larger scales?
we can only assume there are planets made with a rocky core or a gas core. there are some planets we don't know what is beneath the atmosphere, for all we know there are planets composed entirely of liquid, the gravity would hold itself together as a perfect sphere. I'm sure more experiments can confirm this. take honey for example, it has so much surface tension, even though on earth it will spread all over the place and make a mess, in zero g's it won't move an inch without being acted upon, it has so much surface tension that in space it is the LEAST messiest food, surprisingly. but they spilled some in the air somehow, and two drops clumped together, these two drops did not form a sphere, or if they did it took quite some time. the surface tension will hold liquid together but how it will balance it into a perfect sphere is beyond me
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I did not say to edit my signature soulidarity! Now forever I will never remember what I said about understanding the secrets of the universe by paying attention to subtleties!
I'm never giving you the password again. Jerk
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ChuangTzu
starvingphysicist



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Re: so in theory in space....... [Re: imachavel]
#14905778 - 08/11/11 10:45 AM (12 years, 9 months ago) |
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imachavel said: then why would it form a perfect sphere?
Because a sphere has the minimum surface area for a given volume of any 3d solid. The same happens when you blow bubbles.
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the surface tension could hold it together relatively easy without it having to form a perfect sphere, it could be ovoid, or geometrical, and still hold together.
Because the surface energy of these solids is higher than that of a sphere.
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and if you leave the water spread out as drops the drops will eventually crash into each other and form a perfect sphere.
I don't think this would be true unless they were the only things in the nearby universe, and over a very long timescale.
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this is what mercury does on earth.
Is it?
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do they really crash or are they attracted to each other?
They are slightly attracted to eachother, but this force is very small.
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why would you think that gravity only exists on larger scales?
Who ever said that?
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we can only assume there are planets made with a rocky core or a gas core. there are some planets we don't know what is beneath the atmosphere, for all we know there are planets composed entirely of liquid, the gravity would hold itself together as a perfect sphere.
This is true, but on that scale the relative influence of gravity and surface tension are reversed.
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I'm sure more experiments can confirm this. take honey for example, it has so much surface tension, even though on earth it will spread all over the place and make a mess,
The surface tension of honey must be rather low, not high. It has high viscosity.
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in zero g's it won't move an inch without being acted upon, it has so much surface tension that in space it is the LEAST messiest food, surprisingly.
Again, high viscosity, low surface tension (the opposite case of water)
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but they spilled some in the air somehow, and two drops clumped together, these two drops did not form a sphere, or if they did it took quite some time.
This actually contradicts your claim that it is gravity which drives the water to form spheres.
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the surface tension will hold liquid together but how it will balance it into a perfect sphere is beyond me 
See my first sentence.
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