Weight of the Earth on the moon?

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Homework Help Overview

The problem involves calculating the weight of the Earth if it were positioned on the moon, with given masses and radii of both celestial bodies. The context suggests a connection to gravitational forces and possibly torques and moments of force.

Discussion Character

  • Exploratory, Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants discuss the gravitational force equation and its application to the scenario. Some express confusion about the relevance of torques and moments of force. Questions arise about whether the situation is analogous to the weight of the moon on the Earth.

Discussion Status

There is acknowledgment of the original poster's equation as correct, and some participants are exploring the implications of distance variations on gravitational effects. The discussion is open, with various interpretations being considered.

Contextual Notes

Participants note the potential complexity introduced by the differing distances from the moon to different parts of the Earth, as well as the philosophical consideration of gravitational interactions.

cosmic_tears
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Hi everyone!
Ok, so here's the problem:
What would be the weight of the Earth if it were on the moon (just try and imagian that :). The masses of the moon and the earth, and their radiuses, are given.
I cannot see what's the trick here.
There are four possible options.
The one that seemed the most logical is :

(GmM)/(R+r)^2
where m - moon mass, M - Earth mass, R - Earth radius, r - moon radius.

But the material it's supposed to be related to is torques and moments of force... I don't see how it's related :-\

I'd be really thankful for help on how to approach this problem.

Thanks!
Tomer.
 
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Is it the same as the weight of the Moon on the Earth?
 
Weight = gravitational force between two object.

P.S. I wonder if the Earth is sitting on me, or I am sitting on the earth?
 
Your idea and equation are correct cosmic_tears.
 
Thank you all!
I simply thought I'm missing something! I thought maybe I should somehow consider the fact that the far side of the Earth is much further away from the moon than the close side, (as opposed to now, when there's hardly any difference).
It made me think about the fact that if you walked into a black hole your legs will probably get torn cause of the different gravity on your body :).
Thanks again!
 

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