The first law of motion. Law of inertia it states that when an object at rest will remain at rest. And object in motion will remain in motion in a straight line unless it acted upon by an external force (unbalanced force) . Inertia is a special case for acceleration because the net force is 0 , (is a tendency of object to resist any change of motion ) , when a force applied the second law of motion takes place and his involve the second law of motion the acceleration.
