Electricity question please help asap?

Question

Answer 1

I am not sure of these types of questions, but,

Try using the formula Fe = (kq1q2)/r^2

Fe = electric force

k = Coulomb's constant = 8.99*10^9N.m^2/C^2

q1, q2 = two different charges = (q1 = 3.6*10^-7C and q2 = -8.1*10^-7C)

r = radius = 12.5cm