How is inertia defined in the context of physics?

Inertia is defined as the tendency of an object to resist changes in its state of motion, which is accurately captured by the selected answer. This principle is rooted in Newton's First Law of Motion, which states that an object at rest will remain at rest, and an object in motion will continue in motion with the same speed and in the same direction unless acted upon by a net external force.

This inherent property of matter means that the more massive an object is, the greater its inertia, and consequently, the more force will be needed to alter its motion. Inertia is not a force itself but rather a characteristic of an object's mass, indicating how difficult it is to change its state, whether at rest or in motion.

While other choices mention aspects related to motion and forces, they do not appropriately encapsulate the concept of inertia. For example, simply stating that an object tends to remain stationary does not account for its behavior when already in motion. Similarly, the idea of force acting on a mass without the context of resistance to change does not accurately capture what inertia entails. Hence, the definition that highlights resistance to changes in motion is the most fitting representation of inertia in physics.