Moon Hoax - Rockets CANNOT work in space | |
DUCM900 User ID: 22454442 Italy 08/23/2012 02:15 PM Report Abusive Post Report Copyright Violation | For you? One of the most ignorant people about space I have ever seen? It was quite real, by the way... Quoting: Dr. Astro [link to home.freeuk.com] Of course you think it was ridiculous, you're laughably ignorant about space. You shill have just sell your soul for this stupid stuff, that's really incredible. Last Edited by IWASTHERE on 08/23/2012 02:30 PM |
Dr. Astro Senior Forum Moderator User ID: 4211721 United States 08/23/2012 02:16 PM Report Abusive Post Report Copyright Violation | For you? One of the most ignorant people about space I have ever seen? It was quite real, by the way... Quoting: Dr. Astro [link to home.freeuk.com] Of course you think it was ridiculous, you're laughably ignorant about space. You shill have just sell you soul for this stupid stuff, that's really incredible. Sorry, wrong link, here you go: [link to home.freeuk.com] I suppose all those amateurs like Maurice are "shills" too for seeing it for themselves... |
DUCM900 User ID: 22454442 Italy 08/23/2012 02:22 PM Report Abusive Post Report Copyright Violation | |
Anonymous Coward User ID: 22433808 United States 08/23/2012 02:28 PM Report Abusive Post Report Copyright Violation | to expand and clarify on the last question-- Quoting: Anonymous Coward 22433808 the maximum exhaust velocities are: Propellant mix - Effective exhaust velocity (m/s) liquid oxygen/liquid hydrogen - 4462 (16,063km/h) liquid oxygen/kerosene (RP-1) - 3510 nitrogen tetroxide/hydrazine - 3369 [link to en.wikipedia.org] "The delta-v needed to achieve low earth orbit starts around 9.4km/s [33,840km/h]". [link to en.wikipedia.org] So the wheels spin at 30km/h but the car travels at 60km/h??? Rocket science -- like real science but without the pesky facts. You're an idiot. A complete idiot. Let's say a rocket is traveling at a ground-relative velocity of 33,840 km/hr (that's faster than your velocity in low earth orbit, the extra delta-V is needed to get you above the atmosphere, but for the sake of the hypothetical let's go with it) and burns in a retrograde direction with an exhaust velocity of 16,063 km/hr. What is the ground-relative velocity of the exhaust at the beginning of the burn? What is the velocity of the exhaust relative to the rocket? Go on, answer these questions. Let's say you're a (not very) useful idiot. A rocket cannot travel faster than the maximum exhaust velocity. A 16,063 km/h exhaust CANNOT propel a rocket through the atmosphere at 33,840 km/h. Period. |
DUCM900 User ID: 22454442 Italy 08/23/2012 02:33 PM Report Abusive Post Report Copyright Violation | Anonymous Coward 22433808 Do you think they used other technology to put satellites in the orbit or not? Last Edited by IWASTHERE on 08/23/2012 02:33 PM |
Anonymous Coward User ID: 22472222 Spain 08/23/2012 02:38 PM Report Abusive Post Report Copyright Violation | to expand and clarify on the last question-- Quoting: Anonymous Coward 22433808 the maximum exhaust velocities are: Propellant mix - Effective exhaust velocity (m/s) liquid oxygen/liquid hydrogen - 4462 (16,063km/h) liquid oxygen/kerosene (RP-1) - 3510 nitrogen tetroxide/hydrazine - 3369 [link to en.wikipedia.org] "The delta-v needed to achieve low earth orbit starts around 9.4km/s [33,840km/h]". [link to en.wikipedia.org] So the wheels spin at 30km/h but the car travels at 60km/h??? Rocket science -- like real science but without the pesky facts. You're an idiot. A complete idiot. Let's say a rocket is traveling at a ground-relative velocity of 33,840 km/hr (that's faster than your velocity in low earth orbit, the extra delta-V is needed to get you above the atmosphere, but for the sake of the hypothetical let's go with it) and burns in a retrograde direction with an exhaust velocity of 16,063 km/hr. What is the ground-relative velocity of the exhaust at the beginning of the burn? What is the velocity of the exhaust relative to the rocket? Go on, answer these questions. Let's say you're a (not very) useful idiot. A rocket cannot travel faster than the maximum exhaust velocity. A 16,063 km/h exhaust CANNOT propel a rocket through the atmosphere at 33,840 km/h. Period. Are you kidding me? Get off my case, ignoramus kid! Tsiolkovsky rocket equation (from wikipedia, the only source that you handle, and badly): "The equation relates the delta-v (the maximum change of speed of the rocket if no other external forces act) with the effective exhaust velocity and the initial and final mass of a rocket (or other reaction engine)." [link to en.wikipedia.org] A tip: 1. Go to the school. 2. Study the basics: mathematics, chemistry, and physics. 3. Develop critical thinking skills, and learn to search about a topic. 4. After all that, come here and waste your free time talking about woo woo rocketry. Period. |
nomuse (not logged in) User ID: 2380183 United States 08/23/2012 03:10 PM Report Abusive Post Report Copyright Violation | to expand and clarify on the last question-- Quoting: Anonymous Coward 22433808 the maximum exhaust velocities are: Propellant mix - Effective exhaust velocity (m/s) liquid oxygen/liquid hydrogen - 4462 (16,063km/h) liquid oxygen/kerosene (RP-1) - 3510 nitrogen tetroxide/hydrazine - 3369 [link to en.wikipedia.org] "The delta-v needed to achieve low earth orbit starts around 9.4km/s [33,840km/h]". [link to en.wikipedia.org] So the wheels spin at 30km/h but the car travels at 60km/h??? Rocket science -- like real science but without the pesky facts. Wheels DON'T spin at MPH -- they spin at RPM. The wheels of a car are in intimate connection with the road. Now change the scenario; substitute a paddle-wheel boat. The paddle goes SLOWER than the boat. Now let's change up for a prop-driven boat. What is the link between the propeller speed (in RPM) and the boat's forward speed? But, alas, the conditions of a rocket are simpler still. What is thrust velocity? It is the velocity at which the propellant leaves the exhaust bell. Which is itself in motion. Good thing, too. Imagine you were flying an fighter plane moving faster than a speeding bullet. Then you fire your guns. The velocity of the plane is added to the muzzle velocity -- otherwise, fighter pilots would shoot themselves down! |
nomuse (not logged in) User ID: 2380183 United States 08/23/2012 03:15 PM Report Abusive Post Report Copyright Violation | The number of rockets is irrelevant to this particular issue. Quoting: Anonymous Coward 22433808 The issue is the MAXIMUM EXHAUST VELOCITY vs VELOCITY REQUIRED FOR LEO (escape velocity). A rocket cannot travel faster than its own exhaust. But...the "Shuttle" does NOT make it to orbital velocity. (Which isn't the same as escape velocity, but never mind). What arrives at the ISS is the Shuttle ORBITER. What happened to the big orange tank and the two giant solid-state rockets? They got left behind long ago. In short, the shuttle SYSTEM delivers payload (the shuttle ORBITER) that is larger than the available delta-V of the propellant. Because the larger part of the MASS that started out on the launch pad never goes anywhere near space. What you seem to be describing here, if it were a firearm, is some really weird rifle that throws cartridge, bolt, pin and receiver down range along with the bullet. Such a gun would go a couple of feet at best! |
Anonymous Coward User ID: 3491129 United States 08/23/2012 03:24 PM Report Abusive Post Report Copyright Violation | |
DUCM900 User ID: 22454442 Italy 08/23/2012 03:28 PM Report Abusive Post Report Copyright Violation | |
Anonymous Coward User ID: 1454359 United States 08/23/2012 03:35 PM Report Abusive Post Report Copyright Violation | |
DUCM900 User ID: 22454442 Italy 08/23/2012 03:38 PM Report Abusive Post Report Copyright Violation | |
Anonymous Coward User ID: 3491129 United States 08/23/2012 03:38 PM Report Abusive Post Report Copyright Violation | Too bad we have to deal with batshit crazy people on this site. Quoting: Anonymous Coward 3491129 Read it and weep. F(1,2) = -F(2,1) ??? However the question for you is Does Space Shuttle's rokets produces flame on space? YES or NO Your question isn't a yes or no proposition. If you are talking Semantics, then no a flame is not produced because no air is burning externally from the fire creating a licking flame Rockets are a chemical explosion. All the chemicals needed to produce the explosion are included in the rocket. They don't need air from an external source to "burn". Fire is different in space as the reaction is encapsulated inside the chemicals expelled by the equipment, but chemicals can still react and give off energy without air. |
Dr. Astro Senior Forum Moderator User ID: 4211721 United States 08/23/2012 03:39 PM Report Abusive Post Report Copyright Violation | to expand and clarify on the last question-- Quoting: Anonymous Coward 22433808 the maximum exhaust velocities are: Propellant mix - Effective exhaust velocity (m/s) liquid oxygen/liquid hydrogen - 4462 (16,063km/h) liquid oxygen/kerosene (RP-1) - 3510 nitrogen tetroxide/hydrazine - 3369 [link to en.wikipedia.org] "The delta-v needed to achieve low earth orbit starts around 9.4km/s [33,840km/h]". [link to en.wikipedia.org] So the wheels spin at 30km/h but the car travels at 60km/h??? Rocket science -- like real science but without the pesky facts. You're an idiot. A complete idiot. Let's say a rocket is traveling at a ground-relative velocity of 33,840 km/hr (that's faster than your velocity in low earth orbit, the extra delta-V is needed to get you above the atmosphere, but for the sake of the hypothetical let's go with it) and burns in a retrograde direction with an exhaust velocity of 16,063 km/hr. What is the ground-relative velocity of the exhaust at the beginning of the burn? What is the velocity of the exhaust relative to the rocket? Go on, answer these questions. Let's say you're a (not very) useful idiot. A rocket cannot travel faster than the maximum exhaust velocity. A 16,063 km/h exhaust CANNOT propel a rocket through the atmosphere at 33,840 km/h. Period. Answer the questions I asked you. |
Dr. Astro Senior Forum Moderator User ID: 4211721 United States 08/23/2012 03:40 PM Report Abusive Post Report Copyright Violation | to expand and clarify on the last question-- Quoting: Anonymous Coward 22433808 the maximum exhaust velocities are: Propellant mix - Effective exhaust velocity (m/s) liquid oxygen/liquid hydrogen - 4462 (16,063km/h) liquid oxygen/kerosene (RP-1) - 3510 nitrogen tetroxide/hydrazine - 3369 [link to en.wikipedia.org] "The delta-v needed to achieve low earth orbit starts around 9.4km/s [33,840km/h]". [link to en.wikipedia.org] So the wheels spin at 30km/h but the car travels at 60km/h??? Rocket science -- like real science but without the pesky facts. You're an idiot. A complete idiot. Let's say a rocket is traveling at a ground-relative velocity of 33,840 km/hr (that's faster than your velocity in low earth orbit, the extra delta-V is needed to get you above the atmosphere, but for the sake of the hypothetical let's go with it) and burns in a retrograde direction with an exhaust velocity of 16,063 km/hr. What is the ground-relative velocity of the exhaust at the beginning of the burn? What is the velocity of the exhaust relative to the rocket? Go on, answer these questions. Let's say you're a (not very) useful idiot. A rocket cannot travel faster than the maximum exhaust velocity. A 16,063 km/h exhaust CANNOT propel a rocket through the atmosphere at 33,840 km/h. Period. Are you kidding me? Get off my case, ignoramus kid! Tsiolkovsky rocket equation (from wikipedia, the only source that you handle, and badly): "The equation relates the delta-v (the maximum change of speed of the rocket if no other external forces act) with the effective exhaust velocity and the initial and final mass of a rocket (or other reaction engine)." [link to en.wikipedia.org] A tip: 1. Go to the school. 2. Study the basics: mathematics, chemistry, and physics. 3. Develop critical thinking skills, and learn to search about a topic. 4. After all that, come here and waste your free time talking about woo woo rocketry. Period. ^This |
DUCM900 User ID: 22454442 Italy 08/23/2012 03:47 PM Report Abusive Post Report Copyright Violation | Too bad we have to deal with batshit crazy people on this site. Quoting: Anonymous Coward 3491129 Read it and weep. F(1,2) = -F(2,1) ??? However the question for you is Does Space Shuttle's rokets produces flame on space? YES or NO Your question isn't a yes or no proposition. If you are talking Semantics, then no a flame is not produced because no air is burning externally from the fire creating a licking flame Rockets are a chemical explosion. All the chemicals needed to produce the explosion are included in the rocket. They don't need air from an external source to "burn". Fire is different in space as the reaction is encapsulated inside the chemicals expelled by the equipment, but chemicals can still react and give off energy without air. The question was not for you, however you dont answer at all. Because the possible answers are 2 YES or NO there are no other scenario in space with those propellants. Period. Last Edited by IWASTHERE on 08/23/2012 04:09 PM |
BoxerLvr User ID: 883595 Puerto Rico 08/23/2012 03:57 PM Report Abusive Post Report Copyright Violation | Too bad we have to deal with batshit crazy people on this site. Quoting: Anonymous Coward 3491129 Read it and weep. F(1,2) = -F(2,1) ??? However the question for you is Does Space Shuttle's rokets produces flame on space? YES or NO Your question isn't a yes or no proposition. If you are talking Semantics, then no a flame is not produced because no air is burning externally from the fire creating a licking flame Rockets are a chemical explosion. All the chemicals needed to produce the explosion are included in the rocket. They don't need air from an external source to "burn". Fire is different in space as the reaction is encapsulated inside the chemicals expelled by the equipment, but chemicals can still react and give off energy without air. The question was not for you, however you dont answer at all. Because the possible answers are 2 YES or NO there are no other scenario in space with those propellers. Period. Spacecraft don't use propellers!!! It is precisely because it is fashionable for Americans to know no science, even though they may be well educated otherwise, that they so easily fall prey to nonsense. They thus become part of the armies of the night, the purveyors of nitwittery, the retailers of intellectual junk food, the feeders on mental cardboard, for their ignorance keeps them from distinguishing nectar from sewage. — Isaac Asimov |
nomuse (not logged in) User ID: 2380183 United States 08/23/2012 03:57 PM Report Abusive Post Report Copyright Violation | The question was not for you, however you dont answer at all. Because the possible answers are 2 Quoting: DUCM900 YES or NO there are no other scenario in space with those propellers. Period. Does a crossbow giraffe? Answer yes or no, please -- it has to be one or the other. Nonsense. Your question is nonsense, your understanding is wrong, therefore a simple answer is at best misleading. |
Saddletramp User ID: 22023873 United States 08/23/2012 04:02 PM Report Abusive Post Report Copyright Violation | Moontards... "And how can a man die better than facing fearful odds, for the ashes of his fathers, and the temples of his Gods..." ~ Horatius "Because he told the truth, and once you've heard the truth, everything else is just cheap whiskey..." "We don't rent pigs!" |
DUCM900 User ID: 22454442 Italy 08/23/2012 04:05 PM Report Abusive Post Report Copyright Violation | |
Anonymous Coward User ID: 22433808 United States 08/23/2012 04:07 PM Report Abusive Post Report Copyright Violation | to expand and clarify on the last question-- Quoting: Anonymous Coward 22433808 the maximum exhaust velocities are: Propellant mix - Effective exhaust velocity (m/s) liquid oxygen/liquid hydrogen - 4462 (16,063km/h) liquid oxygen/kerosene (RP-1) - 3510 nitrogen tetroxide/hydrazine - 3369 [link to en.wikipedia.org] "The delta-v needed to achieve low earth orbit starts around 9.4km/s [33,840km/h]". [link to en.wikipedia.org] So the wheels spin at 30km/h but the car travels at 60km/h??? Rocket science -- like real science but without the pesky facts. Wheels DON'T spin at MPH -- they spin at RPM. The wheels of a car are in intimate connection with the road. Now change the scenario; substitute a paddle-wheel boat. The paddle goes SLOWER than the boat. Now let's change up for a prop-driven boat. What is the link between the propeller speed (in RPM) and the boat's forward speed? But, alas, the conditions of a rocket are simpler still. What is thrust velocity? It is the velocity at which the propellant leaves the exhaust bell. Which is itself in motion. Good thing, too. Imagine you were flying an fighter plane moving faster than a speeding bullet. Then you fire your guns. The velocity of the plane is added to the muzzle velocity -- otherwise, fighter pilots would shoot themselves down! "Wheels DON'T spin at MPH -- they spin at RPM." Brilliant..and when the the surface of the tire moves (spins)at the speed of the car, in this example, 30 km/h, the car cannot travel 60 km/h. The propeller example is utterly irrelevant. The paddle example is completely incorrect. The paddle wheels circumference moves at or above the speed of the boat, never below. If the paddle went slower, it would have a braking effect on the boat. As to the bullet, its velocity is constantly decreasing after being fired and its propulsion is derived from being trapped between the escaping gas and the end of the barrel; there is no propelling force exerted upon the bullet after it leaves the barrel. The bullet is propelled as the exploding gas 'pushes off' the far more massive, speeding aircraft ..and then it (the bullet) immediately begins decelerating. Unlike a bullet, a rocket is being 'pushed' by its escaping exhaust and can maintain or even increase its velocity (unlike the decelerating bullet) but this velocity can be no greater than that of its exhaust. The rocket boys seem to think that just because the decreasing mass associated with the burning fuel allows the rocket to accelerate (gain velocity as opposed to maintaining a constant velocity) that--somehow - this magically allows the rocket to accelerate to a velocity greater than that of its exhaust-- which is typical NASA nonsense. It can accelerate, but not beyond the velocity of its own exhaust. Acceleration and maximum velocity are apples and oranges. |
DUCM900 User ID: 22454442 Italy 08/23/2012 04:08 PM Report Abusive Post Report Copyright Violation | |
Dr. Astro Senior Forum Moderator User ID: 22479442 United States 08/23/2012 04:09 PM Report Abusive Post Report Copyright Violation | Impulse momentum, High-school physics; Quoting: Anonymous Coward 22471929 Force = (change in momentum)/(time interval) Thrust = (Exhaust Speed)*(Rate of change of Rocket's Mass) As you can see the thrust generated is independent from the interaction of the propellent with the surrounding environment. This video illustrates the principle behind rocket propulsion and how it is an application of momentum conservation. Bump for the idiots, since this already gives away the answer. |
DUCM900 User ID: 22454442 Italy 08/23/2012 04:16 PM Report Abusive Post Report Copyright Violation | to expand and clarify on the last question-- Quoting: Anonymous Coward 22433808 the maximum exhaust velocities are: Propellant mix - Effective exhaust velocity (m/s) liquid oxygen/liquid hydrogen - 4462 (16,063km/h) liquid oxygen/kerosene (RP-1) - 3510 nitrogen tetroxide/hydrazine - 3369 [link to en.wikipedia.org] "The delta-v needed to achieve low earth orbit starts around 9.4km/s [33,840km/h]". [link to en.wikipedia.org] So the wheels spin at 30km/h but the car travels at 60km/h??? Rocket science -- like real science but without the pesky facts. Wheels DON'T spin at MPH -- they spin at RPM. The wheels of a car are in intimate connection with the road. Now change the scenario; substitute a paddle-wheel boat. The paddle goes SLOWER than the boat. Now let's change up for a prop-driven boat. What is the link between the propeller speed (in RPM) and the boat's forward speed? But, alas, the conditions of a rocket are simpler still. What is thrust velocity? It is the velocity at which the propellant leaves the exhaust bell. Which is itself in motion. Good thing, too. Imagine you were flying an fighter plane moving faster than a speeding bullet. Then you fire your guns. The velocity of the plane is added to the muzzle velocity -- otherwise, fighter pilots would shoot themselves down! "Wheels DON'T spin at MPH -- they spin at RPM." Brilliant..and when the the surface of the tire moves (spins)at the speed of the car, in this example, 30 km/h, the car cannot travel 60 km/h. The propeller example is utterly irrelevant. The paddle example is completely incorrect. The paddle wheels circumference moves at or above the speed of the boat, never below. If the paddle went slower, it would have a braking effect on the boat. As to the bullet, its velocity is constantly decreasing after being fired and its propulsion is derived from being trapped between the escaping gas and the end of the barrel; there is no propelling force exerted upon the bullet after it leaves the barrel. The bullet is propelled as the exploding gas 'pushes off' the far more massive, speeding aircraft ..and then it (the bullet) immediately begins decelerating. Unlike a bullet, a rocket is being 'pushed' by its escaping exhaust and can maintain or even increase its velocity (unlike the decelerating bullet) but this velocity can be no greater than that of its exhaust. The rocket boys seem to think that just because the decreasing mass associated with the burning fuel allows the rocket to accelerate (gain velocity as opposed to maintaining a constant velocity) that--somehow - this magically allows the rocket to accelerate to a velocity greater than that of its exhaust-- which is typical NASA nonsense. It can accelerate, but not beyond the velocity of its own exhaust. Acceleration and maximum velocity are apples and oranges. OK, so with which technology / propellent did they use to go in space (if they did). |
EvenT6HorizoN User ID: 12833553 United States 08/23/2012 04:20 PM Report Abusive Post Report Copyright Violation | to expand and clarify on the last question-- Quoting: Anonymous Coward 22433808 the maximum exhaust velocities are: Propellant mix - Effective exhaust velocity (m/s) liquid oxygen/liquid hydrogen - 4462 (16,063km/h) liquid oxygen/kerosene (RP-1) - 3510 nitrogen tetroxide/hydrazine - 3369 [link to en.wikipedia.org] "The delta-v needed to achieve low earth orbit starts around 9.4km/s [33,840km/h]". [link to en.wikipedia.org] So the wheels spin at 30km/h but the car travels at 60km/h??? Rocket science -- like real science but without the pesky facts. Wheels DON'T spin at MPH -- they spin at RPM. The wheels of a car are in intimate connection with the road. Now change the scenario; substitute a paddle-wheel boat. The paddle goes SLOWER than the boat. Now let's change up for a prop-driven boat. What is the link between the propeller speed (in RPM) and the boat's forward speed? But, alas, the conditions of a rocket are simpler still. What is thrust velocity? It is the velocity at which the propellant leaves the exhaust bell. Which is itself in motion. Good thing, too. Imagine you were flying an fighter plane moving faster than a speeding bullet. Then you fire your guns. The velocity of the plane is added to the muzzle velocity -- otherwise, fighter pilots would shoot themselves down! "Wheels DON'T spin at MPH -- they spin at RPM." Brilliant..and when the the surface of the tire moves (spins)at the speed of the car, in this example, 30 km/h, the car cannot travel 60 km/h. The propeller example is utterly irrelevant. The paddle example is completely incorrect. The paddle wheels circumference moves at or above the speed of the boat, never below. If the paddle went slower, it would have a braking effect on the boat. As to the bullet, its velocity is constantly decreasing after being fired and its propulsion is derived from being trapped between the escaping gas and the end of the barrel; there is no propelling force exerted upon the bullet after it leaves the barrel. The bullet is propelled as the exploding gas 'pushes off' the far more massive, speeding aircraft ..and then it (the bullet) immediately begins decelerating. Unlike a bullet, a rocket is being 'pushed' by its escaping exhaust and can maintain or even increase its velocity (unlike the decelerating bullet) but this velocity can be no greater than that of its exhaust. The rocket boys seem to think that just because the decreasing mass associated with the burning fuel allows the rocket to accelerate (gain velocity as opposed to maintaining a constant velocity) that--somehow - this magically allows the rocket to accelerate to a velocity greater than that of its exhaust-- which is typical NASA nonsense. It can accelerate, but not beyond the velocity of its own exhaust. Acceleration and maximum velocity are apples and oranges. OK, so with which technology / propellent did they use to go in space (if they did). Liquid Hydrogen, if I am not mistaken? "I collapsed a lung, screaming at the face of ignorance. I fell victim to the excuse of hatered." - Crater "I disapprove of what you say, but I will defend to the death your right to say it" - Voltaire "Some feel the rain, others just get wet" - Bob Marley |
Rocketfag User ID: 22463777 United States 08/23/2012 04:22 PM Report Abusive Post Report Copyright Violation | |
DUCM900 User ID: 22454442 Italy 08/23/2012 04:31 PM Report Abusive Post Report Copyright Violation | ... Quoting: nomuse (not logged in) 2380183 Wheels DON'T spin at MPH -- they spin at RPM. The wheels of a car are in intimate connection with the road. Now change the scenario; substitute a paddle-wheel boat. The paddle goes SLOWER than the boat. Now let's change up for a prop-driven boat. What is the link between the propeller speed (in RPM) and the boat's forward speed? But, alas, the conditions of a rocket are simpler still. What is thrust velocity? It is the velocity at which the propellant leaves the exhaust bell. Which is itself in motion. Good thing, too. Imagine you were flying an fighter plane moving faster than a speeding bullet. Then you fire your guns. The velocity of the plane is added to the muzzle velocity -- otherwise, fighter pilots would shoot themselves down! "Wheels DON'T spin at MPH -- they spin at RPM." Brilliant..and when the the surface of the tire moves (spins)at the speed of the car, in this example, 30 km/h, the car cannot travel 60 km/h. The propeller example is utterly irrelevant. The paddle example is completely incorrect. The paddle wheels circumference moves at or above the speed of the boat, never below. If the paddle went slower, it would have a braking effect on the boat. As to the bullet, its velocity is constantly decreasing after being fired and its propulsion is derived from being trapped between the escaping gas and the end of the barrel; there is no propelling force exerted upon the bullet after it leaves the barrel. The bullet is propelled as the exploding gas 'pushes off' the far more massive, speeding aircraft ..and then it (the bullet) immediately begins decelerating. Unlike a bullet, a rocket is being 'pushed' by its escaping exhaust and can maintain or even increase its velocity (unlike the decelerating bullet) but this velocity can be no greater than that of its exhaust. The rocket boys seem to think that just because the decreasing mass associated with the burning fuel allows the rocket to accelerate (gain velocity as opposed to maintaining a constant velocity) that--somehow - this magically allows the rocket to accelerate to a velocity greater than that of its exhaust-- which is typical NASA nonsense. It can accelerate, but not beyond the velocity of its own exhaust. Acceleration and maximum velocity are apples and oranges. OK, so with which technology / propellent did they use to go in space (if they did). Liquid Hydrogen, if I am not mistaken? Yes but you did disagree: liquid oxygen/liquid hydrogen - 4462 (16,063km/h) so what? |
Dr. Astro Senior Forum Moderator User ID: 22479442 United States 08/23/2012 04:32 PM Report Abusive Post Report Copyright Violation | |
EvenT6HorizoN User ID: 12833553 United States 08/23/2012 04:37 PM Report Abusive Post Report Copyright Violation | ... Quoting: Anonymous Coward 22433808 "Wheels DON'T spin at MPH -- they spin at RPM." Brilliant..and when the the surface of the tire moves (spins)at the speed of the car, in this example, 30 km/h, the car cannot travel 60 km/h. The propeller example is utterly irrelevant. The paddle example is completely incorrect. The paddle wheels circumference moves at or above the speed of the boat, never below. If the paddle went slower, it would have a braking effect on the boat. As to the bullet, its velocity is constantly decreasing after being fired and its propulsion is derived from being trapped between the escaping gas and the end of the barrel; there is no propelling force exerted upon the bullet after it leaves the barrel. The bullet is propelled as the exploding gas 'pushes off' the far more massive, speeding aircraft ..and then it (the bullet) immediately begins decelerating. Unlike a bullet, a rocket is being 'pushed' by its escaping exhaust and can maintain or even increase its velocity (unlike the decelerating bullet) but this velocity can be no greater than that of its exhaust. The rocket boys seem to think that just because the decreasing mass associated with the burning fuel allows the rocket to accelerate (gain velocity as opposed to maintaining a constant velocity) that--somehow - this magically allows the rocket to accelerate to a velocity greater than that of its exhaust-- which is typical NASA nonsense. It can accelerate, but not beyond the velocity of its own exhaust. Acceleration and maximum velocity are apples and oranges. OK, so with which technology / propellent did they use to go in space (if they did). Liquid Hydrogen, if I am not mistaken? Yes but you did disagree: liquid oxygen/liquid hydrogen - 4462 (16,063km/h) so what? I disagree with this thread, yes. "I collapsed a lung, screaming at the face of ignorance. I fell victim to the excuse of hatered." - Crater "I disapprove of what you say, but I will defend to the death your right to say it" - Voltaire "Some feel the rain, others just get wet" - Bob Marley |
Anonymous Coward User ID: 22433808 United States 08/23/2012 04:43 PM Report Abusive Post Report Copyright Violation | Impulse momentum, High-school physics; Quoting: Anonymous Coward 22471929 Force = (change in momentum)/(time interval) Thrust = (Exhaust Speed)*(Rate of change of Rocket's Mass) As you can see the thrust generated is independent from the interaction of the propellent with the surrounding environment. This video illustrates the principle behind rocket propulsion and how it is an application of momentum conservation. Bump for the idiots, since this already gives away the answer. Rocket boys and their videos. If it's in a video (with a real professor and a table and everything!) it must be true, right? "As you can the the thrust generated is independent from the interaction of the propellent with the surrounding environment." What??? We see no such thing. Were it so, what would be the function of a rocket nozzle? And why all the effort to develop "altitude compensating nozzles" if, as you claim, the thrust is "independent from the interaction of the propellent with the surrounding environment"? Try again. And for the record, the velocity of experimental vehicle shown in the video most certainly did not exceed that of its exhaust velocity. You have confused mathematical formulas with reality. Good luck with that. |