The electrostatic force between two charges is given by Coulomb's law:
[tex]F=k_e \frac{q_1 q_2}{r^2} [/tex]
where
ke is the Coulomb's constant
q1 is the first charge
q2 is the second charge
r is the separation between the two charges
By substituting the data of the problem into the equation, we can find the magnitude of the force between the two charges:
[tex]F=(8.99 \cdot 10^{9} Nm^2C^{-2} ) \frac{(3.5 \cdot 10^{-6} N/C)(2.8 \cdot 10^{-6}N/C)}{(0.28m)^2}=1.2 N [/tex]
