Which describes the 1D gravitational force in this figure?

[Westin]

Homework Statement

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1)Which describes the 1D gravitational force in this figure. (+x is to the right.)

a)Something else.
b)Fgrav=−GMmx2
c)Fgrav=+GMmx22)In moving the little mass m from x1 to infinity the force of gravity does _____________ work.

a) positive
b) negative
c) no

I added an attachment for the figure

Homework Equations

The Attempt at a Solution

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I only have one attempt at it so I want to make sure my logic is right.

1) I think the answer is Fgrav=−GMmx2 because the little mass is going away from the gravitational pull
2) Because of my explanation in #1, I believe the answer is negative

 

[mfb]

I agree.

because the little mass is going away from the gravitational pull

We don't know where the mass is going, but x is going in the "away" direction.