The floor pushing up as a person pushes down illustrates which law?

The floor pushing up as a person pushes down illustrates which law?

• A. Newton's Third Law of Motion
• B. Newton's Second Law of Motion
• C. The Law of Inertia
• D. Law of Universal Gravitation

Answer: (A)

This is an example of Newton's Third Law: for every action there is an equal and opposite reaction. When you push downward on the floor, you exert a force on the floor. In response, the floor pushes upward on you with the same magnitude in the opposite direction—the normal force that supports you. These two forces form an action-reaction pair and act on two different objects: you and the floor. This is not about how fast you accelerate (that would involve the net force and Newton's Second Law) or about gravity alone; it's about the pair of forces that arises from two objects pushing on each other.

This is an example of Newton's Third Law: for every action there is an equal and opposite reaction. When you push downward on the floor, you exert a force on the floor. In response, the floor pushes upward on you with the same magnitude in the opposite direction—the normal force that supports you. These two forces form an action-reaction pair and act on two different objects: you and the floor. This is not about how fast you accelerate (that would involve the net force and Newton's Second Law) or about gravity alone; it's about the pair of forces that arises from two objects pushing on each other.