Paul Hewitt, known for his textbook "Conceptual Physics," defines inertia as the tendency of an object to resist changes in its motion. He emphasizes that inertia is not a force; it's a property of matter that describes its resistance to acceleration. Here are the key points of his definition:

* Inertia and Mass: Inertia is directly proportional to an object's mass. The more massive an object is, the more inertia it has, and the harder it is to get it moving or to stop it once it's in motion.

* States of Motion: Inertia applies to both objects at rest and objects in motion. An object at rest will remain at rest unless acted upon by a net force, and an object in motion will continue in motion at a constant velocity unless acted upon by a net force.

* Everyday Examples: Hewitt uses numerous everyday examples to illustrate inertia, like the feeling of being thrown forward when a car suddenly brakes, or the experience of being thrown backward when a car accelerates.

Hewitt's approach focuses on making the concept of inertia accessible and understandable through everyday experiences. He emphasizes the importance of understanding inertia as a fundamental property of matter that plays a crucial role in understanding how objects move and interact with each other.