find the distance between two stones each of mass 2 kg so that the gravitational force between them is 1n.

Or: F = (Gm1m2)/r^{2}

So, we know that the gravitational constant is 6.67x10^{-11} and that F = 1 and m1 and m2 = 2

So, 1 = (6.67x10^{-11} x 2 x 2)/r^{2}

rearranging, we get r^{2 }= 6.67x10^{-11} x 2 x 2

therefore r^{2} = 2.6692x10^{-10} therefore r = 1.634x10^{-5} m

Or about 16 billionths of a metre.

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