The law that describes the motion of an object with a net force of 0 is Newton's First Law of Motion, also known as the Law of Inertia.

Here's why:

* Newton's First Law: An object at rest stays at rest, and an object in motion stays in motion at a constant velocity (constant speed and direction) unless acted upon by a net force.

* Net Force of 0: When the net force acting on an object is zero, it means all the forces acting on the object balance each other out. There's no unbalanced force to cause a change in the object's motion.

Therefore, if the net force on an object is 0, it will either remain at rest or continue moving at a constant velocity.