* Inertia is the tendency of an object to resist changes in its motion. It's directly proportional to the object's mass.

* Size refers to the physical dimensions of an object (length, width, height).

Two objects that are the same size do not always have the same inertia.

Here's why:

* Density: Even if two objects have the same size, they can have different densities. Density is the amount of mass packed into a given volume.

* A small, dense object (like a lead ball) will have more inertia than a large, less dense object (like a balloon filled with air).

* Composition: Objects made of different materials will have different densities, even if they are the same size. A solid steel ball will have more inertia than a hollow plastic ball of the same size.

In summary:

While size can play a role, it's not the only factor determining inertia. Inertia is primarily determined by an object's mass.