# Gravitational field

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1. Nov 5, 2015

### LeoPedranjo

• Moved from another forum, so homework template missing
Hey guys, take a look at this question if you may

Suppose the moon, instead of a sphere, is a disc orbitating the Earth ( the moon's total mass is equal to the disc's total mass), the intern radius of the disc is equal to half the distnce between moon and Earth's center of mass and the external radius equals double of the distance between moon and Earth's CM. Find an algebric expression that determines: a) the variation in the gravitacional field due to the disc in the north pole or south pole. b) the variation in the gravitational field due to the disc in Earth's center of mass.

That is the whole question. Will there be any effect on the poles at all? Considering that the Earth will pull the disc to its center...

Ty

2. Nov 5, 2015

### UncertaintyAjay

Is this a homework question or just a random exercise? If it's hw, it should be posted on the homework forum.

3. Nov 5, 2015

### LeoPedranjo

Its hw, sorry!

4. Nov 6, 2015

### davenn

OK please repost in the appropriate homework section and use the homework template

Dave

5. Nov 6, 2015

### Staff: Mentor

You will have to give an attempt at a solution to get help with this problem.