Final answer:
The use of seatbelts in the event of a crash or sudden stop increases passenger safety by using the principle of impulse, which spreads the force over a longer period, thus reducing the severity of the impact.
Step-by-step explanation:
In the event of a crash or sudden stop, the use of a seatbelt may greatly increase a passenger's chances of surviving and reduce the likelihood of serious injury. This is explained by the physics concept of impulse, which describes the change in momentum of an object when a force is applied over a period of time. Seatbelts and other safety features like airbags work to extend the time over which the deceleration occurs, thereby reducing the force experienced by the passengers.
When a car crashes, there's a sudden change in momentum as the vehicle stops moving. Without a seatbelt, passengers are at greater risk of hitting the interior parts of the car with lots of force over a very short time span. However, a seatbelt extends the time over which the force is applied, allowing for a more gradual stop and lessening the impact. The concept is similar to how crumple zones in cars are designed to absorb energy during a collision, increasing the duration of the impact and reducing the force that reaches the occupants.
This principle of extending the impact time to reduce force is reflected in the effective use of airbags and padded dashboards, which serve to cushion and protect passengers by extending the time over which the body comes to a stop, thereby reducing the force. Government regulations on seatbelt usage reiterates the societal importance of these safety features, as they not only save lives but also reduce long-term medical care costs.