Newton’s law of inertia was created many years before Newton and it was and is still called the law of inertia. This law states that if an object is at rest it will stay at rest until acted on by a force. Inertia is an object's tendency to resist a change in motion. It also states that an object in motion will stay in motion unless a force acts on and changes its velocity. The Law of Inertia assumes there is no friction that can slow down the object down. When an object is balanced and there is no net force acting upon it, the object is at equilibrium.

The best way to show the Law of Inertia is to do so in outer space.
Once an object is at rest it takes a force which is a push or a pull to put the object in motion. Just like if you put a book on the counter (at rest) the book is not going anywhere unless you push it off the table which hs put a force on it. Once an object is in motion it will stay at a constant velocity unless you put a force on it in the opposite direction that it’s moving in. So if you roll a ball ( and there is no friction) the ball will continue rolling until another person stops it and rolls it back to you.