Let's consider the safety regulation that drivers and passengers must wear a seat belt and how it relates to Newton’s First Law of Motion, which states that an object in motion tends to stay in motion unless acted upon by a net external force.
In the context of a car accident, when a vehicle suddenly stops due to a collision, the passengers and the driver inside the vehicle continue to move forward at the same speed the car was traveling. This is because their bodies are in motion and, according to Newton's First Law, they will not stop moving forward by themselves.
Seat belts serve as the external force that restrains passengers, preventing them from being ejected from their seats or colliding with other hard surfaces within the vehicle during a sudden stop or crash. By wearing a seat belt, the driver's and passengers' motions are effectively altered, providing protection by ensuring they remain securely in their seats. This reduces the risk of serious injury or death caused by the effects of inertia when the car abruptly decelerates.
Thus, the regulation requiring seat belts is fundamentally grounded in the principles of physics, specifically Newton's First Law of Motion, underlining the importance of external forces—like seat belts—in controlling and mitigating the consequences of motion during a crash.