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 #34777 - 06/07/10 02:58 PM Re: Orion, Mission to Alpha Centauri paul Megastar Registered: 03/21/06 Posts: 4136 Quote: For linear motion, after you've transferred some momentum internally and made the outer pipe move, the mass you moved has to stop, and when it does, it cancels out any momentum it gave the pipe to begin get real now kallog.it may take several minutes to equalize the pressures in the tank and pipe.durring this process momentum is being transfered to the pipe giving itlinear acceleration and momentum thus the pipe moves in a linear directionfor a linear distance.and continues to move in that direction.any resistive forces that could apply are not stored up inside the pipe then released when equalization occurs.so the pipe is still moving , it has momentum , but is no longer acceleratingnor decelerating.now you also can not decelerate the pipe by re-pumping theair back into the tank.because you would have equal and opposite reactionsoccuring between the pump and the air tank.but once youve compressed the tank again you can stopthe pipe by releasing the air in the opposite direction.Quote: Although I do see your point that when you're immersed in one common set of knowledge it's hard to come up with new, different ideas. Most good new ideas come from young people who don't have such a long lifetime of the same old thing. when you are trained to fail its hard to succede.because you know you cant , youve been taught thatyou cant , therefore no one else can either. _________________________ 3/4 inch of dust build up on the moon in 4.527 billion years,LOL and QM is fantasy science. Top
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 #34780 - 06/08/10 03:54 AM Re: Orion, Mission to Alpha Centauri [Re: paul] kallog Megastar Registered: 03/17/10 Posts: 1100 Originally Posted By: pauland continues to move in that direction.It doesn't continue to move, it stops. The pipe had momentum while it was moving, but it soon transfers that to the internal gasses travelling in the opposite direction, stopping them both.Please read the post I made earlier listing the states of the system. Tell me where you disagree.Just saying "it'll keep moving because I was taught in school that moving things keep moving" doesn't work, you were taught wrong, sorry.Quote:when you are trained to fail its hard to succede. When you know nothing, it's hard to succeed either. Notice that the world it full to bursting with people having no science education, but they're not inventing perpetual motion or propellent-free rockets. I wonder why. Some of them are inventing mechanical gadgets, things that just require ingenuity, intelligence, effort and lucky good ideas. But they're not tearing down these solidly established theories. Top
 #34781 - 06/08/10 04:40 AM Re: Orion, Mission to Alpha Centauri paul Megastar Registered: 03/21/06 Posts: 4136 Quote:The pipe had momentum while it was moving, but it soon transfers that to the internal gasses the pipe is moving , you say it had momentum then the momentum of the pipe !!!!! transfers to the gasses.How is the pipe going to transfer momentum to the gasses?that will be a good one.the only time that the air comming out of the tank can provide any resistanceto pipe movement is WHILE THE AIR IS COMMING OUT of the tank.and WHILE THE AIR IS COMMING OUT OF THE TANK , THE PIPE IS MOVING.and it continues to move. _________________________ 3/4 inch of dust build up on the moon in 4.527 billion years,LOL and QM is fantasy science. Top
 #34785 - 06/08/10 08:22 AM Re: Orion, Mission to Alpha Centauri [Re: paul] kallog Megastar Registered: 03/17/10 Posts: 1100 Originally Posted By: paulHow is the pipe going to transfer momentum to the gasses? When they hit the pipe or indirectly via collisions with other gas molecules which then hit the pipe.Do you honestly not understand this? It's just a very simple application of the law of conservation of momentum. Top
 #34790 - 06/08/10 12:32 PM Re: Orion, Mission to Alpha Centauri paul Megastar Registered: 03/21/06 Posts: 4136 I myself have a very clear understanding of what happens.I was questioning your understanding.you state that the momentum moves the pipe , and you obviously are talking about the momentum of the air in the pipe , and then you state that at the same time the airis stopping the pipe.if the air is causing movement or supplying a force for movement then it must be supplying more force than theresistance for movement that the air is also supplyingaccording to your assumption.you cant have it both ways.the air mass inside the pipe has moved from inside the tankand distributed to the rest of the pipe.some of the mass moved over 400 ft.some moved over 300 ft -->some moved over 200 ft -->some moved over 100 ft -->some small amount moved <--- between the pipe and the tank.I cant understand your reasoning that the pipe will stop?if you dont mind could you explain at which point the pipelooses all momentum and stops? _________________________ 3/4 inch of dust build up on the moon in 4.527 billion years,LOL and QM is fantasy science. Top
 #34791 - 06/08/10 02:02 PM Re: Orion, Mission to Alpha Centauri [Re: paul] kallog Megastar Registered: 03/17/10 Posts: 1100 Originally Posted By: paulyou state that the momentum moves the pipe , and you obviously are talking about the momentum of the air in the pipe , and then you state that at the same time the airis stopping the pipe.Yes, the air both starts it and stops it, not at the same time of course because each air molecule takes some time to slow down.Quote:I cant understand your reasoning that the pipe will stop?if you dont mind could you explain at which point the pipelooses all momentum and stops? I'll simplify it to be a gun instead of a rocket, and it's fixed to the front of the pipe, pointing backwards.You fire the gun, and it gives momentum -p1 to the bullet. At the same time it gives momentum p1 to the gun and pipe. Exactly the same as recoil in a normal gun.Clearly the pipe's now moving because it has momentum p1.Eventually the back end of the pipe and the bullet collide, and the bullet becomes embedded in the back of the pipe. They were travelling in opposite directions, with zero total momentum (-p1 + p1 = 0). Now they're a single solid object with the same total momentum - 0.The pipe has 0 momentum and has therefore stopped moving.Please let me know if you think:- Using a bullet analogy is a good enough idealization whether my explanation is correct or not.- You agree with it but think it differs too much from the air jet case. Top
 #34800 - 06/08/10 03:59 PM Re: Orion, Mission to Alpha Centauri [Re: paul] ImagingGeek Senior Member Registered: 05/19/10 Posts: 410 Loc: Canada Originally Posted By: paulQuote: No, I am not. m*Ve is zero when you do not have a nozzle which allows for expansion. if its ZERO then NOTHING will come out.Wrong, as [Po-Pe](Ae) is non-zero. Ergo you'll have F = 0 + X, where X is equal to whatever [Po-Pe](Ae) equals.Remember - the formula is the sum, not the multiple of those two terms. A zero on one side of the sum doesn't make the total a zero.Bryan _________________________ UAA...CAUGCUAUGAUGGAACGAACAAUUAUGGAA Top
 #34801 - 06/08/10 04:01 PM Re: Orion, Mission to Alpha Centauri ImagingGeek Senior Member Registered: 05/19/10 Posts: 410 Loc: Canada Originally Posted By: kallogHey, not that I know what that formula's all about but have you two both totally overlooked this really simple miscommunication?- Paul says Ve is velocity- Imaginggeek says Ve is zeroJust saying it back and forth to each other doesn't change the fact that you're obviously talking about different quantities!!!! Actually, Paul and I agree on this - Ve is a velocity. Where paul is wrong is in how that velocity is calculated - it is the velocity ADDED to the air coming out of the tank, due to the acceleration of the gas caused by a divergent nozzle.Paul stated the air was coming out of a tube - i.e. there is no divergence. As such Ve (keeping in mind, Ve is the added velocity, not the absolute velocity) will be zero.Bryan _________________________ UAA...CAUGCUAUGAUGGAACGAACAAUUAUGGAA Top
 #34802 - 06/08/10 04:59 PM Re: Orion, Mission to Alpha Centauri paul Megastar Registered: 03/21/06 Posts: 4136 I have already solved the equation in message #34760and it is clearly shown what I was telling you.that BOTH the sums are included for the solution to the equation.Quote: F = (m × Ve) + (Pe - Pa) × Aeair has a mass of 0.0807 lb / cu ft0.0807 / 1728 = 0.000046701388 lbs / cu inthe area is 1 sq inch so air at 6.828 atm has a mass of 6.828 X 0.000046701388 = 0.000318877077264 pound mass0.000318877077264 pounds = 0.000144640209 kilogramsm = 0.000144640209 kilograms100 pounds = 45.359237 kilogramsa = F/m45.359237 kg / 0.000144640209 kg = 313600.466382069 m/s^2F=(0.000144640209 * 313600.466382069 m/s^2)+ (Pe - Pa) × AeF=(45.359)+ (Pe - Pa) × AeF=(45.359)+ (689.47kPa-101kPa)*0.00064516m^2F=(45.359)+ 588.47kPa * 0.00064516m^2F= 45.359 + 0.3796573052 F = 45.738894305199934012421 N45 kilograms = 99.208018 pounds F = (m × Ve) + (Pe - Pa) × Aeany one knowing any math at all would know thatthe above equation is basicaly 1 + 1 = ?which is the what the basic formula is. you didnt even use the correct pressure you used apx 1400 psi to start with , knowing it was only 100 psi.Quote:Because we don't have a cone, m*Ve is zero. Therefore, the amount of thrust at a full tank is:F = (Pt-Pa)*AeF = (10132kPa-101kPa)*0.00064516m^2F = 6471NAs the tank empties and the pipe fills, that force will drop. Thrust ends when Pt = Pa.100 psi is NOT 10132 Pa !!!!!1 psi = 6.895 kPa !!!! LOOK IT UP.and on top of that you botched the results from those two numbers.ie....F=(10132kPa - 101kPa)* 0.00064516m^2 = 6.47N6.47N not 6471Nwhat I think you needed was good ole cheat sheet.using your atrocity of an result by only using the 0.37N and not adding the 45.35N would of course work in YOUR FAVOR WOULDNT IT? _________________________ 3/4 inch of dust build up on the moon in 4.527 billion years,LOL and QM is fantasy science. Top
 #34805 - 06/08/10 05:26 PM Re: Orion, Mission to Alpha Centauri [Re: paul] ImagingGeek Senior Member Registered: 05/19/10 Posts: 410 Loc: Canada Originally Posted By: paul100 psi is NOT 10132 Pa !!!!!1 psi = 6.895 kPa !!!! LOOK IT UP.My bad, I used ATA in place of PSI for some reason.Originally Posted By: pauland on top of that you botched the results from those two numbers.ie....F=(10132kPa - 101kPa)* 0.00064516m^2 = 6.47N6.47N not 6471NNope, you botched up the calc. A kPa is kilo-Pascals, as in 1000 pascals. You have to multiple kPa by 1000 to get the Pa needed in the formula used above - ergo:F = (10132kPa - 101kPa)* 0.00064516m^2F = (10132000Pa - 101000Pa) * 0.00064516m^2F = 6471N, AKA 6.47kNOriginally Posted By: paulwhat I think you needed was good ole cheat sheet.No, I need to check my work, although I have to say the exact values mean little here; it is the basic physical principals that are important.Originally Posted By: paulusing your atrocity of an result by only using the 0.37N and not adding the 45.35N would of course work in YOUR FAVOR WOULDNT IT?Nope, not one iota. Regardless of the magnitude of the force, the physics are the same. 0.37N or 2,000,000,000N, its all the same in the end - the pressurized tank will exert that force forwards on the pipe, while the air coming out the back of the tank will exert that same force rearwards on the tank. Net force is zero either way - whether you've got nano-newtons or giga-newtons (although the later may destroy the pipe completely...)Bryan Edited by ImagingGeek (06/08/10 05:32 PM) _________________________ UAA...CAUGCUAUGAUGGAACGAACAAUUAUGGAA Top
 #34806 - 06/08/10 05:31 PM Re: Orion, Mission to Alpha Centauri paul Megastar Registered: 03/21/06 Posts: 4136 Quote: When you have a pressurized gas being released by a tank there are two potential sources of thrust - the pressure pushing the gas out of the tank, and the expansion of that compressed gas once it leaves the tank. this is not a thrust that is the result of combustiblegasses , it is simply air that is compressed.I would like to see your results from the followingformula.F=m*Vand your explaination of it.although it is a absolute meaningless part of the formulaaccording to you , do you honestly think that there will be no mass comming out of the tube therefore there will be zero velocity. _________________________ 3/4 inch of dust build up on the moon in 4.527 billion years,LOL and QM is fantasy science. Top
 #34807 - 06/08/10 05:45 PM Re: Orion, Mission to Alpha Centauri [Re: paul] paul Megastar Registered: 03/21/06 Posts: 4136 I didnt botch it up , I worked it exactly as you posted it.meaning that I need to check all of your formulas plus your math.F=(10132kPa - 101kPa)* 0.00064516m^210132000Pa is still 1469.52 psi...again you botched it up.even after you aknowledged the initial mistake.you still get 6471Nand that is wrong.it really doesnt matter what the amount of thrust is anyway.it can be fast or slow but faster is better in this case.as I have stated before the thrust is not what MOVES the pipe.the momentum of the mass moving inside the pipe is what movesthe pipe.do you deny that the air mass moving inside the pipe wouldmove the pipe? _________________________ 3/4 inch of dust build up on the moon in 4.527 billion years,LOL and QM is fantasy science. Top
 #34809 - 06/08/10 06:13 PM Re: Orion, Mission to Alpha Centauri paul Megastar Registered: 03/21/06 Posts: 4136 Quote: the pressurized tank will exert that force forwards on the pipe, while the air coming out the back of the tank will exert that same force rearwards on the tank. so according to you , there would be no force exerted onto the sides of the pipe?and dont forget those same exact forces are exerted to the front of the pipe as well , you cant just have it your way.but the forces from the air as it leaves the tank pressing against the pipe is not what will cause the pipe to move.it is the mass of air that is moving inside the pipe from one place in front to the rest of the inside of the pipe.the tube only slows down the time that the mass moves. _________________________ 3/4 inch of dust build up on the moon in 4.527 billion years,LOL and QM is fantasy science. Top
 #34810 - 06/08/10 06:17 PM Re: Orion, Mission to Alpha Centauri [Re: paul] ImagingGeek Senior Member Registered: 05/19/10 Posts: 410 Loc: Canada Originally Posted By: paulI didnt botch it up , I worked it exactly as you posted it.meaning that I need to check all of your formulas plus your math.F=(10132kPa - 101kPa)* 0.00064516m^2You did not work it exactly as posted. Had you done that you'd have done the calcs using kilopascals, as indicaterd in what I wrote. You didn't, despite the fact kPa was typed out.Ergo, my math is right, ignoring the PSI vs ATA foopah...Originally Posted By: paulit can be fast or slow but faster is better in this case.In your case the speed of the gas will always be the same - the speed of sound. Originally Posted By: pauldo you deny that the air mass moving inside the pipe would move the pipe?It would. But that change in momentum would be countered by an equal, but opposite momentum due to the momentum of the tank the air was contained in. Thus total change in your pipes momentum would be zero. It may rock back and forth, but it isn't going to go anywhere.Its that later half you always miss - anytime you give something momentum in a closed system, you get an equal but opposite momentum produced. It doesn't matter which of those you use as a reference point - in the end, the net change in momentum will always be zero.Bryan _________________________ UAA...CAUGCUAUGAUGGAACGAACAAUUAUGGAA Top
 #34811 - 06/08/10 06:21 PM Re: Orion, Mission to Alpha Centauri paul Megastar Registered: 03/21/06 Posts: 4136 if there was a piston sitting in the tube , then your calculations state that the piston would not move.or would the piston move.would the pressurized air present a force to the piston?I already know it would , but for some reason it seems that you think it would just sit there even though itonly has 14.7 psi on the other end.Im about to throw my arms up in the air and mark you off as a candidate to use as a tool to deny funding that should apply to work with the idiots at the D.O.E. _________________________ 3/4 inch of dust build up on the moon in 4.527 billion years,LOL and QM is fantasy science. Top
 #34812 - 06/08/10 06:26 PM Re: Orion, Mission to Alpha Centauri [Re: paul] ImagingGeek Senior Member Registered: 05/19/10 Posts: 410 Loc: Canada Originally Posted By: paulQuote: the pressurized tank will exert that force forwards on the pipe, while the air coming out the back of the tank will exert that same force rearwards on the tank. so according to you , there would be no force exerted onto the sides of the pipe?I never said that; if you're only counter-argument is to twist my words you've already lost.The increasing pressurization of the pipe has no impact on the numbers what-so-ever, as this pressurization occurs equally in all directions.However, the air expelled from the tank does have momentum in one direction - opposite to the direction of the momentum of the tank. Momentum is not pressure, and therefor the equalization of pressure in the pipe has nothing to do with where that momentum goes.Originally Posted By: pauland dont forget those same exact forces are exerted to the front of the pipe as well , you cant just have it your way.Wrong, wrong and wrong again. I know repetition doesn't help in your case, but momentum is not pressureMomentum Is Not PressureMOMENTUM IS NOT PRESSUREChanges of pressure in the pipe have nothing to do with the momentum in this system. Why you'd bring it up is a mystery to me (actually, it isn't, since you've consistently mixed up the differences between force, pressure, momentum and energy).Originally Posted By: paulbut the forces from the air as it leaves the tank pressing against the pipe is not what will cause the pipe to move.it is the mass of air that is moving inside the pipe from one place in front to the rest of the inside of the pipe.So you now think that the momentum of the air in your tank is divorced from the forces which produce that momentum?Its an interesting world you live in, where things move without forces acting on them.In the real world things don't work that way - force and momentum are intimately intertwined; you cannot create one without creating/changing the other. Application of forces change momentum, momentums transfer forces. Bryan _________________________ UAA...CAUGCUAUGAUGGAACGAACAAUUAUGGAA Top
 #34813 - 06/08/10 06:30 PM Re: Orion, Mission to Alpha Centauri paul Megastar Registered: 03/21/06 Posts: 4136 do you even know anything about momentum.if the air mass moves from the tank , the air itself is not really moving , the pipe is what moves.the pipe moves out of the way of the air.because the pressures inside are equalizing.the air mass moves inside the pipe because the air pressure is equalizing. _________________________ 3/4 inch of dust build up on the moon in 4.527 billion years,LOL and QM is fantasy science. Top
 #34814 - 06/08/10 06:45 PM Re: Orion, Mission to Alpha Centauri paul Megastar Registered: 03/21/06 Posts: 4136 there really is nothing that your twisting of words and math can accomplish with me that is , I know Im right eventhough you have repeatedly re-stated the same old stuff over and over , never once admitting that the mass of air comming out of the nozzle has velocity , simply because the nozzle isnt really a nozzle.a nozzle only focuses the thrust.in this case a nozzle is not the reason there is a thrustthe thrust comes from the m*Ve.but your genius rejects that concept.so why do they bother putting fuel in jet aircraft all they really need is a nozzle.paul is just using a tube therefore no velocity , right!!!if I have a rifle and I cut the barrel off just beyond thebullet , according to your genius the bullet would just stay there when I fired the riffle.because the bullet doesnt have a barrel , ohhhh poor poor bullet.it cant go nowhere because ImageingGeeks math comprehension =ZERO.and you call people stupid.now I suppose you will do exactly the same with the momentum of air that moves inside the pipe.there obviously will be no momentum in the moving airright?just like the magic tube.only now its the magic moving air with no mometum.just because you write a lot of words and use twisted mathdoesnt mean youre saying anything. _________________________ 3/4 inch of dust build up on the moon in 4.527 billion years,LOL and QM is fantasy science. Top
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