If first law of motion holds true, why does a ball rolling on ground stop on its own?
The first law of motion states that if a body is moving or at rest, it will remain in motion or rest unless an external force is applied. If a ball rolling on the ground stop on its own, it is due to friction a force over the surface of the ground which opposes the motion and brings down the motion of the rolling ball to rest. That's why the rolling ball on the ground stops on its own.