Final answer:
The net force acting on an object is the sum of the individual forces when they are acting in the same direction, and it is calculated as the vector sum of these forces.
Step-by-step explanation:
The net force acting on an object equals the sum of the individual forces when the two forces are acting in the same direction. Forces are vector quantities, meaning they have both magnitude and direction, and when calculating the net force, one must consider both of these aspects. According to Essential Knowledge 3.B.1, if an object interacts with several other objects, the net force is the vector sum of the individual forces. This concept is fundamental in understanding how forces combine and how they affect the object's motion.