Inertia is the tendency of an object to resist changes in its motion. The more massive an object is, the more inertia it has.

Here's why:

* Mass is a measure of inertia: A larger mass means a greater resistance to changes in motion.

* 20 kg is much greater than 2 mg: A 20 kg object has a mass 10,000 times greater than a 2 mg object.

Therefore, the 20 kg object has significantly more inertia than the 2 mg object.