Moment of inertia is a measure of an object's resistance to changes in its rotational motion. It depends on the object's mass distribution and its shape.
Even if an object is stationary, it still has a moment of inertia.
Here's why:
* Moment of inertia is an intrinsic property: It's a characteristic of the object itself, determined by its mass and how that mass is distributed.
* Rotation is not required: The object can be at rest and still possess a moment of inertia.
Think of it this way:
* A door at rest has a moment of inertia. If you try to push it open, you'll feel the resistance. This resistance is due to the door's moment of inertia.
* A spinning top has a moment of inertia. This is why it continues to spin, even after you've stopped pushing it.
In summary: An object can have a non-zero moment of inertia even if it's not rotating. Rotation is about the object's *motion*, while moment of inertia is about its *resistance to changes in motion*.
