Inertia is the tendency of an object to resist changes in its state of motion. This means an object at rest wants to stay at rest, and an object in motion wants to stay in motion at the same speed and direction.

Weightlessness does not mean the absence of gravity. It means the absence of a *normal force* pushing back on an object. This occurs when an object is in freefall, like an astronaut orbiting Earth.

Here's why a high-mass object exhibits inertia in weightless conditions:

1. Inertia is inherent: An object's inertia is directly proportional to its mass. A more massive object has more inertia. This means it takes more force to change its motion.

2. Weightlessness doesn't remove mass: Even though an object in freefall experiences weightlessness, its mass remains the same.

3. Inertia persists: Since the mass hasn't changed, the inertia of the object also hasn't changed.

In weightlessness:

* If the high-mass object is at rest, it will remain at rest unless a force acts on it.

* If the high-mass object is in motion, it will continue moving at a constant velocity (speed and direction) unless a force acts on it.

Example: Imagine a bowling ball floating in space. It's weightless, but it still has a lot of inertia. If you push it, it will start moving, and it will be difficult to stop because of its high mass and inertia.

Key Point: Inertia is a fundamental property of matter. It is independent of whether or not an object is in a gravitational field or experiencing weightlessness.