Answer to Question #341067 in Electricity and Magnetism for lance

Question

the mass of a typical car is m= 1000 kg, so its weight on earths surface is mg=9800N. suppose you have two containers, one with N electrons and another with N protons. these two containers are placed a distance 10m apart, and the electric force between them is equal to the weight of the car. Find N

Answer 1

$F=\frac{N^2ke^2}{r^2},$

$N=\frac re\sqrt\frac Fk=6.5\cdot 10^{16}.$