Here's why:
* Inertia is the tendency of an object to resist changes in its motion.
* Mass is the amount of matter in an object.
Inertia is directly proportional to mass. This means that a more massive object has a greater tendency to resist changes in motion than a less massive object.
Therefore, if two objects have the same mass, they will have the same inertia.
What can affect how an object *appears* to have more inertia?
* Distribution of Mass: Even if two objects have the same total mass, the way that mass is distributed can influence how they respond to forces. A hollow sphere, for example, might be easier to rotate than a solid sphere of the same mass.
* Shape: The shape of an object can also influence its inertia. For example, a long, thin rod is easier to rotate than a thick, round disk.
* Friction: Friction can make it seem like an object has more inertia because it opposes motion.
Let me know if you have any other questions about inertia or mass!
