Here's why:

* Newton's First Law of Motion (Law of Inertia): An object at rest stays at rest, and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.

This means:

* Stationary objects: They will remain at rest unless a force pushes or pulls them to move.

* Moving objects: They will continue moving at the same speed and direction unless a force causes them to slow down, speed up, or change direction.

In essence, inertia is the tendency of an object to resist changes in its state of motion. Whether the object is currently moving or not, it will resist any change in its motion.