Physics practice test. Help!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Question

Two electrons are passing 20 mm apart.what is the electric repulsive force that they exert on each other?(The valu of k is 9*10^9 N-m^2/c^2)

Answer 1

Find electric repulsive force using

F=kq1q2/d^2

Here q1 and q2 are  the strengths of electrons,d is distance between electrons and k Coulomb's constant.

strengths of electrons,q1=q2=1.602 x 10-19. C

Substitute ,q1=q2=1.602 x 10-19. C,k=9*10^9 N-m^2/c^2 and d=20 mm

F=(9*10^9)(1.602 x 10-19)(1.602 x 10-19)/(0.02)^2

   =0.5766422350752*10^-24 N