Answer:
The displacement is zero
Explanation:
Displacement is a vector that connects the starting position of motion of an object to the final position. It is a vector quantity, so it has both magnitude and direction.
Viceversa, distance is a scalar quantity that measures the total length of the path covered by the object during its motion.
In this problem, we are interested in the displacement.
We are told that the runner goes around a 1 mile track, and he ends at his starting position: this means that his final position is equal to the starting position, therefore the displacement is zero.
