Final answer:
Newton's third law of motion is observed when standing on the ground; the Earth and person exert forces on each other. The person's force is equal and opposite to Earth's gravitational pull, which is experienced as the ground pushing up, known as the normal force.
Step-by-step explanation:
When standing on the ground and feeling the ground pushing up at our feet, we are experiencing Newton's third law of motion. This law states that for every action, there is an equal and opposite reaction. In the context of a person standing on Earth, the Earth exerts a gravitational force pulling the person toward it, and in response, the person exerts a force that is equal in magnitude but opposite in direction, effectively pushing Earth away. However, due to the vast difference in mass, the Earth's movement is imperceptible.
Additionally, we can understand this concept further through the normal force, which is the force that opposes the weight of an object and is perpendicular to the surface of contact. In standing still, the normal force is what one feels as the ground pushing up, counteracting gravity and preventing us from sinking into the ground.