Which of the following statements is true about inertia?

Inertia is defined as the resistance of any physical object to any change in its velocity, which includes changes to the object's speed or direction. This property means that an object will remain at rest or continue to move at a constant velocity unless acted upon by an external force. The correct statement clearly conveys that inertia is the tendency of an object to resist changes in its state of rest or motion, encapsulating the fundamental concept established by Newton's first law of motion.

This understanding of inertia is crucial in physics as it relates to how objects behave under various conditions, emphasizing that an object at rest will stay at rest, and an object in motion will maintain its motion unless influenced by an outside force. Inertia does not depend on whether an object is in motion; it is an inherent property of all objects regardless of their state, which distinguishes it from forces or other interactions involved when an object is acted upon. This is why the alternative statements are not accurate representations of inertia.