What property of objects describes their resistance to changes in motion?

The property that describes an object's resistance to changes in its motion is known as inertia. Inertia is a fundamental concept in physics that relates directly to 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 at a constant velocity unless acted upon by a net external force. This means that objects with more mass have greater inertia, making them harder to accelerate or decelerate.

In everyday terms, when you push or pull an object, its mass determines how much it will resist that change in motion. For example, pushing a heavy box requires more force than pushing a light one because the heavy box has greater inertia. This principle is essential in understanding motion and the effects of forces acting on different objects, making inertia a key concept in both classical and modern physics.