Question

How far apart must two protons be if the electrical force acting on either one is equal to its weight on the earth's surface when the mass of proton is 1.7×10^-27kg

Answer 1

G M m / R^2 = F force of attraction for proton

K e^2 / r^2 = F force of attraction between 2 protons

G M m / R^2 = K e^2 / r^2

r^2 = K e^2 R^2 / (G M m)

r^2 = 9E9 * (1.6E-19)^2 * (6.37E6)^2 / (6.67E-11 * 5.98E24 * 1.7E-27)

r^2 = 9 * 2.56 * 40.6 / (6.67 * 5.98 * 1.7) * 10^-19

r^2 = 1.38 * 10^-30

r = 1.17E-15 m