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Thread: Gravititional force

  1. #1 Gravititional force 
    Forum Freshman almirza's Avatar
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    The Earth is moving around it self but we do not feel that motion because of the atmosphere and also it is moving around the sun . Also we do not feel that motion for the same reason , or what?

    There is a gravititional force between the earth and the moon but why it's rotating around the Earth what I mean is why it is not moving towards the Earth?
    And if we go to the space do all thing rotate around us??????


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  3. #2  
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    For the first question I think your answer isn't a good answer .imagin that you are a small dot in a paper then you think your world is very big and you think it is in one place with no moving and if some one moves the paper he moves your world but you can't understand that it is because you are so small and you are a part of your world (the paper) ...
    It is this way for us too ,we are a part of our earth system and again if we go to moon it is the same story and the world doesn't rotate around us.
    About your other question why moon doesn't fall into the earth ? I think that moon is a distance that the force of its scape of earth because of its rotation is equal to gravity force and it cannaot scape or fall into earth. :wink:


    The important thing is not to stop questioning. Curiosity has its own reason for existing.
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  4. #3  
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    The moon doesn't fall into the earth because both are also falling towards the sun. The moon doesn't go around the earth but they pass each other out during this fall. The moon is deflected toward the earth during it's fall towards the sun and each pass each other in turn. However both don't fall into the sun because the sun is also falling toward something else. The moon isn't going around in a circle in space but travelling in a wavelike manner through space. Hope this helps and also hope it's right. It seems the solutions of gravity are just pushed on to the next further away object.
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  5. #4  
    Forum Professor wallaby's Avatar
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    i just breezed over this topic so i'll be breif.

    the moon doesn't fall into the earth because its orbital velocity and distance from the earths gravitational pull alow it to stay in orbit. it is true that the moon is in free fall although it never gets closer than normal to the earth.
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  6. #5 But... 
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    I agree with your answer ... but it is not the solution friend! anyone else?
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  7. #6 Re: But... 
    Forum Ph.D. william's Avatar
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    Quote Originally Posted by livenomercy
    I agree with your answer ... but it is not the solution friend! anyone else?
    _______________
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    Now that's a clever way to spam the forum!
    "... the polhode rolls without slipping on the herpolhode lying in the invariable plane."
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  8. #7 Re: Gravititional force 
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    Quote Originally Posted by almirza
    The Earth is moving around it self but we do not feel that motion because of the atmosphere and also it is moving around the sun . Also we do not feel that motion for the same reason , or what?

    There is a gravititional force between the earth and the moon but why it's rotating around the Earth what I mean is why it is not moving towards the Earth?
    And if we go to the space do all thing rotate around us??????
    You do feel the effect of the rotation of the Earth. It causes a light decrease in your weight. But the effect is small.

    The effect of the revolution of the Earth around the sun is smaller.

    The moon is actually moving slowly away from the earth due to tidal effects. The moon does not fall into the earth because it is in a stable orbit, just like other satellites but farther out.

    Rotation is a relative term. You can choose coordinates so that all things rotate around us. That is not a particularly conventient choice.

    You might want to read a book on orbital mechanics. Orbital Mechanics by Prussing and Conway is a nice readable introduction.
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