What does net force mean?

The simple interest on a loan of 200$ at 10% per year is

Between 1518 and 1548, spanish conquistadores conquered most of the new world, motivated by the a) desire for scientific knowledge. b)  to urge to claim more territory for spain. c) belief that an all-water western route to the orient existed. d) desire to advance national glory, serve god, and seek personal wealth.

Compared with the executive and legislative branches