Answer:
[tex]F=5.75\cdot 10^6 N[/tex]
Explanation:
The magnitude of the electrostatic force between two charged objects is given by Coulomb's law:
[tex]F=k\frac{q_1 q_2}{r^2}[/tex]
where:
[tex]k=8.99755\cdot 10^9 Nm^{-2}C^{-2}[/tex] is the Coulomb's constant
[tex]q_1, q_2[/tex] are the two charges  of the two objects
r is the separation between the two objects
In this problem, the two objects are the two clouds, so we have:
[tex]q_1 = 43 C[/tex] (charge of the 1st cloud)
[tex]q_2=-43 C[/tex] (charge of the 2nd cloud)
r = 1.7 km = 1700 m (distance between the two clouds)
So the force between them is
[tex]F=(8.98755\cdot 10^9)\frac{(43)(-43)}{1700^2}=-5.75\cdot 10^6 N[/tex]
So, the magnitude of the force is (neglecting the negative sign which indicates that the force is attractive)
[tex]F=5.75\cdot 10^6 N[/tex]
