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Rockets need an atmosphere to propel | |
Balance242 (OP) User ID: 76708078  Canada01/23/2019 11:44 PM Report Abusive Post Report Copyright Violation | |
| Dillmiester User ID: 77154896  United States01/23/2019 11:44 PM Report Abusive Post Report Copyright Violation | |
| Balance242 (OP) User ID: 76708078 Canada01/23/2019 11:47 PM Report Abusive Post Report Copyright Violation | I think the problem is that you don't seem to realize that gasses have mass, and you don't understand the relationship between mass, velocity, and momentum. Quoting: Frumpelstiltskin When you drop a mass from your hand from a height, does it push back on your hand? Didn’t the mass gain momentum? Balance242 |
| Balance242 (OP) User ID: 76708078 Canada01/23/2019 11:48 PM Report Abusive Post Report Copyright Violation | |
| Dillmiester User ID: 77154896 United States01/23/2019 11:49 PM Report Abusive Post Report Copyright Violation | |
| Frumpelstiltskin User ID: 77177702 United States01/23/2019 11:49 PM Report Abusive Post Report Copyright Violation | I think the problem is that you don't seem to realize that gasses have mass, and you don't understand the relationship between mass, velocity, and momentum. Quoting: Frumpelstiltskin When you drop a mass from your hand from a height, does it push back on your hand? Didn’t the mass gain momentum? Rockets don't "drop" fuel/exhaust, they "push" it. If you "pushed" the mass toward the ground, it would exert a palpable force upon your hand. --'-,{@ |
| Balance242 (OP) User ID: 76708078 Canada01/23/2019 11:50 PM Report Abusive Post Report Copyright Violation | |
| Dillmiester User ID: 77154896 United States01/24/2019 12:11 AM Report Abusive Post Report Copyright Violation | Say you have a hose with a nozzle its on the hose off but under pressure, the water isnt moving till it starts and continues to escape, the idea is to move it through faster. The point at where it leaves continually it will travel in that direction its aimed notice the same hose taking off effect happens regardless if the pressure nozzle is on or not like bare hose wide open just moves around a lot less faster, The stream is smaller in diameter and less water volume with the pressure nozzle it may sustain its own weight with the water turned to like 30 percent for example but the open end hose only gently flails around with it maxed out. Lets say for sake of the argument every bit of that exhaust was captured immediately upon exiting the nozzle it would still move. Last Edited by Dillmiester on 01/24/2019 12:15 AM |
| Balance242 (OP) User ID: 76708078 Canada01/24/2019 12:12 AM Report Abusive Post Report Copyright Violation | I think the problem is that you don't seem to realize that gasses have mass, and you don't understand the relationship between mass, velocity, and momentum. Quoting: Frumpelstiltskin When you drop a mass from your hand from a height, does it push back on your hand? Didn’t the mass gain momentum? Rockets don't "drop" fuel/exhaust, they "push" it. If you "pushed" the mass toward the ground, it would exert a palpable force upon your hand. The rocket doesn’t push it. The combustion of fuel creates hot gases and creates a large pressure difference between the rocket chamber and space. It is pressure gradient force that moves the exhaust. [link to m.youtube.com (secure)] Balance242 |
| Dillmiester User ID: 77154896 United States01/24/2019 12:19 AM Report Abusive Post Report Copyright Violation | |
| Frumpelstiltskin User ID: 77177702 United States01/24/2019 12:23 AM Report Abusive Post Report Copyright Violation | I think the problem is that you don't seem to realize that gasses have mass, and you don't understand the relationship between mass, velocity, and momentum. Quoting: Frumpelstiltskin When you drop a mass from your hand from a height, does it push back on your hand? Didn’t the mass gain momentum? Rockets don't "drop" fuel/exhaust, they "push" it. If you "pushed" the mass toward the ground, it would exert a palpable force upon your hand. The rocket doesn’t push it. The combustion of fuel creates hot gases and creates a large pressure difference between the rocket chamber and space. It is pressure gradient force that moves the exhaust. [link to m.youtube.com (secure)] The higher pressure gradient increases the velocity at which the particles are expelled, hence the increased change in the rocket's momentum. --'-,{@ |
| Mike in Southampton User ID: 77177514  United Kingdom01/24/2019 01:40 AM  Report Abusive Post Report Copyright Violation | |
| Balance242 (OP) User ID: 76708078 Canada01/24/2019 07:09 AM Report Abusive Post Report Copyright Violation | Most threads I would agree. This particular subject is a fail. 10 pages of this is like trying to explain math to a cat. And yet no simple experiment showing that there is an equal and opposite force due to movement from pressure gradient force. When the wind blows on your back, did the air in front of you push on your face when it moved away from you? Balance242 |
Dr. Deplorable Astromut Senior Forum Moderator 01/24/2019 09:20 AM  Report Abusive Post Report Copyright Violation | |
| Dr. Deplorable Astromut Senior Forum Moderator 01/24/2019 09:22 AM Report Abusive Post Report Copyright Violation | Quoting: Dr. Deplorable Astromut No chamber. The surrounding space doesn't get pressurized.  |
| Anonymous Coward User ID: 54600209 United States01/24/2019 10:45 AM Report Abusive Post Report Copyright Violation | |
| sunwatcher User ID: 76808308  Brazil01/24/2019 12:14 PM Report Abusive Post Report Copyright Violation | Firing a starting pistol in space will still generate recoil fuckwit. Quoting: (*)(*) No, I said firing a bullet is not equivalent to a rocket, however firing a blank is. Quoting: Balance242 If it’s just gun powder not encapsulated in something, then no it won’t produce thrust. Why would the gunpowder have to be "encapsulated in something?" It's mass, it doesn't matter if it's one large piece of mass or many smaller pieces. So in your opinion, a gun firing blanks in a vacuum would have absolutely no recoil, but a bullet would? How about buckshot? It's still mass, but now it's a cluster of smaller pieces of mass. How about bird shot? How about progressively smaller and smaller individual pellets of mass? Now how about just tiny bits of soot and lots of gas? Will it still have any recoil? Yes it will. Newton's laws don't stop working just because you're spewing literal tons of gas instead of solid mass. so, if only the mass, not its FORM, matters for the "recoil" (that cause the ship changing its orientation)... provided any kind of mass is thrown, why use gas that has less mas per cm3 than water for instance or even iron pellets? less space for mass storage needed, for a same autonomy of a given maneuver ability(?) I got confused. I know "solid" fuel that can be "burned" to throw gas can be used but if only mass "matters" (no pun intended), why not just "drop" solid mass pieces (say, "pellets") of some material with MORE mass per cm3 than solid fuels, saving "fuel" storage space, for kind of maneuvers that don't require "fine tunning" for directions a gas is more appropriate (like just moving straight ahead)? Last Edited by sunwatcher on 01/24/2019 12:15 PM I'm becoming an expert in identifying bikes'n'boats thanks to GLP |
| sunwatcher User ID: 76808308 Brazil01/24/2019 12:17 PM Report Abusive Post Report Copyright Violation | If the airflow can lift a pennies, shouldn’t the opposite force be at least great then the normal force of the penny. This would be easily seen on the scale. Quoting: Balance242 it could also lift a vagina as well? (I couldn't resist lol) I'm becoming an expert in identifying bikes'n'boats thanks to GLP |
| Dr. Deplorable Astromut Senior Forum Moderator 01/24/2019 12:31 PM Report Abusive Post Report Copyright Violation | so, if only the mass, not its FORM, matters for the "recoil" (that cause the ship changing its orientation)... provided any kind of mass is thrown, why use gas that has less mas per cm3 than water for instance or even iron pellets? Quoting: sunwatcher Mass flow rate is only one part of the equation. Exhaust velocity is the over riding factor for efficiency. Hydrogen as a fuel is a very light element, but it has an exhaust velocity around 4.4 km/s in various hydrolox engines like the space shuttle main engines. You're not going to be able to propel iron pellets that fast and it actually is a "water" engine; the product of combusting it with liquid oxygen is H2O. For ion engines the velocity is imparted using electrical energy rather than chemical reactions, so heavy elements ARE used, it's why they typically pick Xenon as the reaction mass. It's actually has more mass per atom than iron. Last Edited by Astromut on 01/24/2019 12:31 PM |
| Anonymous Coward User ID: 77305190 United States01/24/2019 01:28 PM Report Abusive Post Report Copyright Violation | He continually keeps avoiding giving any useful information about the test setup, even a simple picture that would expose the flaws in his experiment like the type of scale used which makes a huge difference if it isn't something like a precious metal scale, he only offers the fact that pennies weigh "approx 3 grams each". Quoting: Dillmiester The larger the scale usually the more innacurate it becomes when dealing with small weights. I’m working on a video...will come soon. Anyhow it would save me the trouble if you could Come up we a simple experiment showing an opposite force due to pressure differential Anyone know any free movie editing software? Ok great, you're basically implying your video will overturn two thousands years of of physics since the Magi of ancient Persia first preposed. Can't wait to research this and to redo my doctorate thesis taking into account your new thermal dynamics model. Please get back to us , once you get a clue. of basic physics.  |
| Balance242 (OP) User ID: 76708078 Canada01/24/2019 08:48 PM Report Abusive Post Report Copyright Violation | Most threads I would agree. This particular subject is a fail. 10 pages of this is like trying to explain math to a cat. And yet no simple experiment showing that there is an equal and opposite force due to movement from pressure gradient force. When the wind blows on your back, did the air in front of you push on your face when it moved away from you? You've been shown several concluded experiments. Newton's 3rd law is in effect every time. As I said before; you're blind and ignorant. It's not your fault. You were born this way. Name calling is not concluded experiments. Balance242 |
| Balance242 (OP) User ID: 76708078 Canada01/24/2019 08:50 PM Report Abusive Post Report Copyright Violation | So when wind blows on your back, did the air in front of you push on your face when is moved away from you? Quoting: Balance242 That isn't analogous to a rocket at all you fucking idiot. How is it not. Is the gas moving due to pressure gradient? Isn't the wind moving due to pressure gradient? what's the difference? Balance242 |
| Balance242 (OP) User ID: 76708078 Canada01/24/2019 09:01 PM Report Abusive Post Report Copyright Violation | |
| Dr. Deplorable Astromut Senior Forum Moderator 01/24/2019 09:17 PM Report Abusive Post Report Copyright Violation | So when wind blows on your back, did the air in front of you push on your face when is moved away from you? Quoting: Balance242 That isn't analogous to a rocket at all you fucking idiot. How is it not. Is the gas moving due to pressure gradient? Isn't the wind moving due to pressure gradient? what's the difference? Force vectors, you clearly don't understand them. |
| JADR+ User ID: 77314344  Australia01/24/2019 09:20 PM Report Abusive Post Report Copyright Violation | Thread: Will a gun fire in space? I'm a J & proud zio. OrangeManBad NFTs: [link to opensea.io (secure)] FE Challenge: Provide a formula which calculates the exact distance between 2 GPS coordinates that does not use the Earth's radius of 6,371 km in it's assumptions JADR+ |
| Balance242 (OP) User ID: 76708078 Canada01/24/2019 10:04 PM Report Abusive Post Report Copyright Violation | Pressure builds up between the gun chamber and bullet. Pressure pushes the bullet and gun. Like a compressed spring between two blocks. When the spring uncompresses, the spring pushes off both the blocks. A rocket is like a compressed spring attached to only one block. When the spring uncompressed, the spring only pushes the block as much as it pushes the air. Balance242 |
| Balance242 (OP) User ID: 76708078 Canada01/24/2019 10:06 PM Report Abusive Post Report Copyright Violation | So when wind blows on your back, did the air in front of you push on your face when is moved away from you? Quoting: Balance242 That isn't analogous to a rocket at all you fucking idiot. How is it not. Is the gas moving due to pressure gradient? Isn't the wind moving due to pressure gradient? what's the difference? Force vectors, you clearly don't understand them. not a sufficient explanation. Balance242 |
| JADR+ User ID: 77314344 Australia01/24/2019 10:42 PM Report Abusive Post Report Copyright Violation | Pressure builds up between the gun chamber and bullet. Pressure pushes the bullet and gun. Like a compressed spring between two blocks. When the spring uncompresses, the spring pushes off both the blocks. A rocket is like a compressed spring attached to only one block. When the spring uncompressed, the spring only pushes the block as much as it pushes the air. That does not explain the recoil when shooting. [link to en.wikipedia.org (secure)] Recoil (often called knockback, kickback or simply kick) is the backward movement of a gun when it is discharged. In technical terms, the recoil momentum acquired by the gun exactly balances the forward momentum of the projectile and exhaust gases (ejecta), according to Newton's third law, known as conservation of momentum. In hand-held small arms, the recoil momentum is transferred to the ground through the body of the shooter; while in heavier guns such as mounted machine guns or cannons, recoil momentum is transferred to the ground through the mount. I'm a J & proud zio. OrangeManBad NFTs: [link to opensea.io (secure)] FE Challenge: Provide a formula which calculates the exact distance between 2 GPS coordinates that does not use the Earth's radius of 6,371 km in it's assumptions JADR+ |
| Anonymous Coward User ID: 77305190 United States01/25/2019 01:38 AM Report Abusive Post Report Copyright Violation | ... Quoting: Masiro® "For every action there is an opposite reaction." That is a fundamental law of physics 101. Also known as Newton's third law of motion, it explains why things move because of the force applied to them. Like the wind against my face for instance. Simple question: What pushes the wind against my face? By your reasoning because the atmosphere is there I should not feel anything and there should be no movement. The pennies in the tube lift because of the sudden rush of air out the tube, but if the vacuum process is slowed down to a point where the extraction of the gases in the tube isn't enough to lift the penny, then the penny won't move at all. The variable in your experiment is the speed at which you extract the air inside the tube, you are doing it at a high speed fast enough to raise the weight of a penny. The movement is simply due to pressure difference. This movement is not the same as throwing or pushing an object. If the air flow is strong enough to lift the penny, the force must be at least greater than the normal force of the penny. But this is not seen on the scale, therefore, equal and opposite reaction does not happen. I see you are still confused... The penny moves because of the (Giovanni Battista) Venturi principle, which describes how lift is created by a difference in air pressure, or that when air pressure is lower on one side of an object than the other that low pressure side rises. It's why wings work and has nothing to do with rocket motors. “The Venturi effect is the reduction in fluid pressure that results when a fluid flows through a constricted section (or choke) of a pipe.” That is how the nozzle works. I already explained how the nozzle favors the fact that the exhaust pushes off the atmosphere. Regardless, a force greater than the force of gravity in the penny must be generated to lift the penny against gravity. I didn’t see that opposite force, therefore you are lying. Another dumbass that hasn't a clue. The atmospheric effect or anything behind it is mathematically negligible in how a rocket engine (or ballon let loose) for that matter, in how propulsion works. It is the force on the constricting portion of a nozzle that propels things forwards. |
| Balance242 (OP) User ID: 76708078 Canada01/25/2019 08:55 PM Report Abusive Post Report Copyright Violation | |
