Final answer:
Using safety belts and shoulder belts is crucial as they increase the chance of survival in a collision by preventing ejection and reducing force on the body, which is why they are mandated by law to protect individuals and society as a whole.
Step-by-step explanation:
Using both safety belts and shoulder belts is important because it increases your chances of surviving a collision. Seat belts play a major role in automobile safety by preventing occupants from being ejected from the vehicle during a crash. Additionally, airbags provide substantial protection by deploying upon impact to minimize serious injuries. They do this by allowing the net force on the occupants in the car to act over a much longer time when there is a sudden stop, thereby reducing the force that brings the occupant to a stop.
When vehicles are designed with crumple zones that can absorb the force of the impact, it increases the time of impact, which in turn decreases the force felt by the passengers by increasing the duration over which the force is applied, as explained by the concept of impulse in physics. This longer duration and the crumpling effect of plastic components also contribute to lessening the force during a collision.
Wearing safety belts is also necessary because they are required by law, and society benefits from these laws by reducing the number of injuries and fatalities, which in turn decreases the burden on medical and societal resources. These safety measures reflect society's effort to protect itself from behaviors that might threaten the common welfare, which includes not wearing seat belts.