Question

how can waling on earth be an example of thirld law of motion]

Answer 1

Newton's 3rd law of motion states that:

“For every action there is an equal and opposite reaction.”

It means that for every interaction between objects there are always 2 forces acting. The forces must be equal in magnitude. That is they must both be equally "strong." They also must be opposite - working in opposing directions.

When we walk our foot pushes on the floor and the floor pushes back on us - in the opposite direction, resulting in our moving in the direction we are walking.

It's a little difficult to understand that this happens anytime we have an interaction between objects. When we sit down on a chair, the chair pushes up on us. And, of course, when we hit someone, he/she's going to hit us back

Answer 2

Answer:

Newton's third law: If an object A exerts a force on object B, then object B must exert a force of equal magnitude and opposite direction back on object A. This law represents a certain symmetry in nature: forces always occur in pairs, and one body cannot exert a force on another without experiencing a force itself.