Final answer:
The net force on the runner with an applied force of +40 N against a resistive force of -2 N is 38 N in the direction of the applied force.
Step-by-step explanation:
The net force on the runner you described, given an applied force of +40 N and a resistive force of -2 N, is calculated by summing these forces. Since force is a vector quantity and these two forces are directly opposed to each other (with the positive and negative indicating their opposite directions), the net force is the algebraic sum.
Thus, the net force is 40 N + (-2 N) = 38 N in the direction of the applied force, which in this context is assumed to be the positive direction.