Electric forces

An electron is released above the earth's surface. A second electron directly below it exers just enough of an electric force on the first electron to cancel the gravitational force on it. Find the distance between the two electrons.

I thought if I just set the graviational force to the electric force and solved for R, i would get the answer. But that doesn't work unless you know how far electron 1 is above the earth. Any suggestions?

mg= k e^2/d

solve for d

Assume the electron is near the surface, where weight is mg.

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asked by Sara

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