Inertia is the tendency of an object to resist changes in its motion. Objects at rest stay at rest, and moving objects keep moving unless acted on. Inertia is present in all objects with mass. It is a basic property of matter.

Inertia is observed in everyday situations, such as when a moving object continues in the same direction. It applies to objects on Earth and in space. Different objects have different amounts of inertia.

Inertia is described in physics as part of motion and matter. It is related to the mass of an object. This concept is used in many scientific studies.