What is Newton's First Law generally termed?

• A. Law of Gravity
• B. Law of Inertia
• C. Third Law of Motion
• D. Law of Thermodynamics

Answer: (B)

Newton's First Law centers on inertia—the resistance of any object to changes in its motion. If no net external force acts on an object, it stays at rest or moves with constant velocity in a straight line. This idea is why the law is commonly called the Law of Inertia.

Think of a puck sliding on a frictionless ice surface: it would keep gliding at the same speed and direction unless something—like friction or a push—acts on it. That tendency to maintain motion or rest without external influence is exactly what inertia describes.

The other options refer to different principles: gravity describes attraction between masses, the third law covers action-reaction force pairs, and the law of thermodynamics deals with energy and entropy. So the term that best captures the concept of resisting changes in motion is the Law of Inertia.