Question

which principle explains why a sprinter needs to take a few steps after crossing the finish line before he can stop?
aerodynamics
newtons second law of motion
centripetal force
gravitational force

Explanation:

A sprinter continues moving after crossing the finish - line due to inertia. Inertia is related to Newton's first law of motion, but among the given options, Newton's second law of motion (which relates force, mass, and acceleration) is the closest relevant concept as the sprinter needs to apply a force (by taking steps) to change their state of motion (slow down). Aerodynamics mainly deals with air - flow around objects, centripetal force is related to circular motion, and gravitational force acts vertically downwards and is not the main reason for the sprinter's need to take steps to stop.

Answer:

Newton's second law of motion