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how high do you have to go before the earths gravitationel field is weak enough for you to float? Answered

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alexhalfordBest Answer (author)2009-06-05

As lemonie said, it's about relative movement. If you're at stand still, theoretically there is no point at which the earth's gravity is non - existent.
Gravity is defined as:
Force = (M1 x M2 x G) / r squared
M1 and M2 are the masses of the two objects concerned. G is the gravitational constant (about 6.67) and r is the distance between the centres of mass of the two objects.
Therefore, as the force approaches 0, the distance approaches infinity.
So, from a physics standpoint, there is no distance at which the earth's gravity, or indeed the gravity of any object, will not exist.

The distance at which it becomes negligible, depends on how sensitive you are =]

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user

actually the formula defines the distance between the ceter of both masses as d squared

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Whether you choose to replace 'r' with 'd' or otherwise, the result is the same. I would suggest, with all due respect, that you endeavour to make useful contributions to the site rather than quibbling about insignificant issues. And I might add, as lemonie said, quotes around a word in this context is generally accepted to mean that the contents thereof are questionable, "sir".

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lemonie (author)mitchell9319932009-06-13

I don't think it does define a distance as d2 - post the correct formula if Mr Halford has got it wrong.

L

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Derin (author)Derin2009-06-22
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lemonie (author)2009-06-03

Zero-G weightlessness is achieved by orbiting, where you're constantly falling towards the Earth but never getting any closer to the ground (through moving around it). Or put another way the effect of gravity is balanced with the "centrifugal" force which would otherwise throw you away from the planet.
To do this you need to be out of the atmosphere (which would slow you down), low Earth orbit starting at ~ 160Km.

To get far enough away as you wouldn't feel the effect at a standstill, I don't know.

L

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mitchell931993 (author)lemonie2009-06-12

actually its centripetal force- not centrifugal

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lemonie (author)mitchell9319932009-06-13

I'm not interested in arguing the difference but I appreciate the comment. Notice that I used the "" on the word? L

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arduinoe (author)lemonie2009-06-15

centrifugal force is inertia that is applied on a spining object w, think flemings left hand rule , only with inertia

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lemonie (author)arduinoe2009-06-15

I know what it is, but I don't see a meaningful comparison with Fleming's rule? L

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