Answer:
[tex]7.6\cdot 10^{-15} m[/tex]
Explanation:
The electrostatic force between two electrons is given by:
[tex]F=k\frac{e^2}{r^2}[/tex]
where
[tex]k=8.99\cdot 10^9 Nm^2C^{-2}[/tex] is the Coulomb's constant
[tex]e=-1.6\cdot 10^{-19}C[/tex] is the electron charge
r is the distance between the two electrons
In this problem, we know F=4.0 N, so we can re-arrange the equation to calculate r:
[tex]r=\sqrt{\frac{ke^2}{F}}=\sqrt{\frac{(8.99\cdot 10^9)(-1.6\cdot 10^{-19})^2}{4.0 N}}=7.6\cdot 10^{-15} m[/tex]
