physics
posted by hashi .
how far apatr should two electrons be if the electric force each exerts on the other is equal to the weight of an electron ? ( take the mass of an electron to be Me = 9.11 x 1031 kg ).

Use F=ma to find the weight of an electron, use a=9.8 m/s^2
use coulombs law
F=k(Q1Q2)/r^2
rearrange to
r^2=k(Q1Q2)/F
use k=8.99 x 10^9 N m^2/C^2
and Q1=Q2=1.60x10^19 C