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Thread: Jet propulsion via conservation of momentum

  1. #1

    Default Jet propulsion via conservation of momentum

    I've been wondering how jet propulsion in space works. Since space is a vacuum, there is nothing for the thrust to act against. For example, when you swim, you propel yourself forward by pushing against the water when you paddle.

    Jet propulsion in space works by the law of conservation of momentum, see http://en.wikipedia.org/wiki/Momentu...inear_momentum.

    I think this is amazing.

  2. #2
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    Which is how those ion propulsion systems work. Incredible...
    Internet the way it was meant to be. Launch details will become Crystal Clear very soon...

  3. #3

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    Yep, force of thrust on the spacecraft not the thrust on anything behind it is what drives it. I was also saucer eyed when I was taught it.
    "The only things that are infinite are the universe and human stupidity, and im not sure about the former"
    Albert Einstein

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    Yep, the more basic explanation for the lay-man would be Newton's 3rd law, "Every action has an equal but opposite reaction". This is true because of the conservation of momentum.
    "Life's journey is not to arrive at the grave safely in a well preserved body, but rather to skid in sideways, totally worn out shouting f#ck, what a ride!"

  5. #5

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    To me, this is just proof that we're making the universe up as we go along. Big chunks of metal full of people shouldn't be able to fly either.
    Quote Originally Posted by icyrus View Post
    Good to see that you are still a bigoted ignorant arsehole. Some things never change.

  6. #6

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    Quote Originally Posted by Frikkenator View Post
    Yep, the more basic explanation for the lay-man would be Newton's 3rd law, "Every action has an equal but opposite reaction". This is true because of the conservation of momentum.
    This is the correct one AFIK
    If it walks like a duck and kwaks like a duck ..its a duck

  7. #7
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    Don't they teach Newton's laws in school any more?
    entia non sunt multiplicanda praeter necessitatem

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    Quote Originally Posted by ponder View Post
    Don't they teach Newton's laws in school any more?
    Lol, I actually remember out science teacher asking us how a rocket is propelled, even after we've learned about Newton's laws. People came up with the grandest theories, only to realise how simple it actually is!

    We were lucky though, had probably one of the best science teachers around!
    "Life's journey is not to arrive at the grave safely in a well preserved body, but rather to skid in sideways, totally worn out shouting f#ck, what a ride!"

  9. #9
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    Jet propulsion doesnt work in space. Jet propulsion requires a fluid. Jets push against the atmosphere. They don't use conservation of momentum. Rockets use conservation of momentum.

    A jet engine draws sucks in air, compresses it and then explosively blows it out the back.

    You can't suck enough in space.

    Rockets don't need to suck in anything.

    http://www.physicsforums.com/archive.../t-108114.html

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