How does newtons first law apply in wearing seat belts in a car wreck

You move forward and stay in motion until an unbalanced force.An unbalanced force is one that is not opposed by an equal and opposite force operating directly against the force intended to cause a change in the object's state of motion or rest. So, when you come to a stop, you wouldn't stop motion unless a force is caused to change your motion and put you at rest. If you were wearing a seat belt, the seat belt would act as the unbalanced force, it would stop you from being in motion.

Try and make the question more clear : )