assume distance of seperarion is 1m
F.elec = kQq/r^2
charge of a proton: 1.6×10^-19 C
charge of a neutron: 0 C
F.elec = 0 N
F.grav = GMm/r^2
mass of a proton: 1.672621898×10^-27 kg
mass of a neutron: 1.674927471×10^-27 kg
F.grav = (6.67408×10^-11)×(1.674927471×10^-27)×(1.672621898×10^-27)÷(1^2)
F.grav = 1.8699588×10^-64 N
