What is the primary focus of Newton's Third Law?

• A. Force can change the state of an object
• B. Gravity affects all objects equally
• C. For every action, there is an equal and opposite reaction
• D. An object’s mass influences its speed

Answer: (C)

Newton's Third Law primarily focuses on the relationship between two objects in an interaction. It states that for every action, there is an equal and opposite reaction. This means that whenever one object exerts a force on a second object, the second object exerts a force of equal magnitude but in the opposite direction on the first object. This principle is fundamental in understanding how forces work in pairs, which is essential in physics and applications such as sports science, where athletes must understand how their movements affect their opponents and the environment around them.

In contrast, other choices touch on different aspects of physics. The first option addresses how forces can alter an object's state, which is part of Newton's First Law. The second option about gravity pertains to specific gravitational principles rather than action-reaction pairs. The last option discusses the relationship between mass and speed, which relates more to Newton's Second Law regarding acceleration rather than focusing on the interaction between forces. These distinctions highlight why the third law stands out in its specific focus on action and reaction.