We will apply the concepts related to Newton's second law. At the same time we will convert everything to the system of international units.

The values of the velocities are,


We know that the acceleration is equivalent to the change of the speed in a certain time therefore



Now applying the Newton's second law we have,



Therefore the approximate magnitude is 8516.36N
North to north repels, south to south repels, north to south attracts, the same vise versa.
The goal of scientific method is to produce public knowledge. That is knowledge available to any person with sufficient education, all such knowledge can be verified by or deduced from experiments and observations.