How is net force calculated?

Which system of units is used by only a small number of countries in the world, including the u.s.

When doing scientific research ,the sources used should be ?

Which of the following situations would produce an average velocity of zero? o a. a horse galloping in a field b. a round-trip to school and back o c. a trip, first to the moon, then onto mars o d. the criss-crossing path of a flying bug