What term describes an object's resistance to changes in its velocity, according to Newton's First Law?

The term that best describes an object's resistance to changes in its velocity, as stated by Newton's First Law, is inertia. Inertia is a fundamental property of matter that indicates how much an object resists any change to its state of motion—whether that state is at rest or moving at a constant speed in a straight line.

According to Newton's First Law, also known as the Law of Inertia, an object will remain at rest or continue moving at a constant velocity unless acted upon by a net external force. This means that the tendency of an object to maintain its current state of motion is directly related to its mass; the more massive an object is, the greater its inertia and, consequently, the more force is required to change its velocity.

Understanding inertia is crucial in applications of physics, as it provides insights into how objects behave in various scenarios, such as in collisions or when forces are applied. For instance, when a car suddenly stops, the passengers continue to move forward due to their inertia, which illustrates this concept in a practical scenario.