## College Physics (4th Edition)

We can find the separation distance between the two charges: $F = \frac{k~q_1~q_2}{r^2}$ $r^2 = \frac{k~q_1~q_2}{F}$ $r = \sqrt{\frac{k~q_1~q_2}{F}}$ $r = \sqrt{\frac{(9.0\times 10^9~N~m^2/C^2)(1~C)(1~C)}{10~N}}$ $r = 3.0\times 10^4~m$ $r = 30~km$ The two charges are 30 km apart.