The amount of matter in an object is called mass. Mass is a fundamental property of an object that measures its inertia.

Here's the breakdown:

* Mass: The amount of matter in an object. It's a scalar quantity, meaning it only has magnitude.

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

So, a heavier object has more mass and therefore more inertia, meaning it's harder to start it moving or to stop it once it's in motion.

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