import math
E0 = 1./(36.*math.pi*10.**9.); # permitivity in free space
k = 4.*math.pi*E0 ;
q1 = 1.; # charge on the first particle in coulombs
q2 = 1.; # charge on the second particle in coulombs
d = 1.; # distance between the particles in meter
F = (q1*q2)/(k*d**2.); # force between the two particles in newtons
print '%s %.e' %("force in free space between the two particles is in Newtons is:",F)