Where Is Zero Gravity Between Earth and Moon?

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Homework Help Overview

The discussion revolves around identifying the point in space between the Earth and the Moon where the gravitational forces from both bodies cancel each other out, resulting in zero weight for an object placed at that point.

Discussion Character

  • Exploratory, Assumption checking

Approaches and Questions Raised

  • Participants explore the concept of gravitational force and its variation with distance, questioning the validity of using surface gravity ratios to determine the zero-gravity point in space.

Discussion Status

Participants have engaged in clarifying the assumptions behind the gravitational force calculations and have suggested that a mathematical approach is necessary to find the exact point of zero gravity. There is an ongoing exploration of how to set up the relevant equations.

Contextual Notes

There is a mention of the surface gravity of the Earth and Moon, and how that ratio does not apply universally in space, indicating a need for careful consideration of gravitational force equations.

nilic1
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Where on an imaginary gravitational field line between Earth and moon, a mass would have no weight neither due Earth nor due to moon?
 
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If you mean when the gravitational force is zero, then you just need to equate

FEarth and FMoon for a mass m and solve for the distance.
 
rock.freak667 said:
If you mean when the gravitational force is zero, then you just need to equate

FEarth and FMoon for a mass m and solve for the distance.

Thanks for your reply. This was meant to be a straight forward answer without any calculation.
Since the gravity of the moon is 1/6 that of Earth , does it follow that the distance where there is no gravity on the object is 1/6 the distance between moon and Earth, starting off from the moon?
 
Last edited:
No, that 1/6 figure is only true about the surface gravity of the Earth vs. the surface gravity of the moon. It is not applicable everywhere in space.

I think you really do need to set up an equation using the equation for gravitational force. At least, I can't imagine solving it any other way.
 
Redbelly98 said:
No, that 1/6 figure is only true about the surface gravity of the Earth vs. the surface gravity of the moon. It is not applicable everywhere in space.

I think you really do need to set up an equation using the equation for gravitational force. At least, I can't imagine solving it any other way.

Thanks for you answer. I did as you both suggested. The final answer is 1/10 the total distance starting from the centre of the moon.

Regards
 

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