If there is no force acting on an object, it will remain at rest if it was initially at rest, or continue moving at a constant velocity if it was already in motion. This is known as Newton's First Law of Motion, also called the law of inertia.

Here's a breakdown:

* Inertia: An object's tendency to resist changes in its state of motion.

* Rest: An object at rest will stay at rest unless acted upon by a force.

* Constant Velocity: An object moving at a constant velocity will continue moving at that velocity unless acted upon by a force.

In simpler terms, if nothing pushes or pulls on an object, it will either stay still or keep moving in a straight line at the same speed.