Which law states that an object in motion stays in motion unless acted upon by an external force?

Newton's First Law of Motion, also known as the Law of Inertia, explains that objects remain in their state of motion unless an external force interferes. This means that an object at rest will stay at rest, and an object in motion will continue moving at a constant velocity unless acted upon by an unbalanced force. In simpler terms, objects tend to resist changes in their motion. This law is fundamental in understanding the behavior of objects in the absence of external forces. It helps explain why objects behave the way they do and is a key concept in physics.