Final answer:
Safety belts should be worn with the lap belt across hip bones and the shoulder strap against the chest. Proper positioning enhances safety and when combined with car safety features like airbags, it reduces force on passengers in accidents.
Step-by-step explanation:
Safety belts should be worn with the lap belt positioned low and snug across the hip bones and the shoulder strap against your chest, not under your arm. This proper positioning is crucial for maximizing safety and effectiveness in the event of an accident. Additionally, understanding the concept of impulse can highlight the importance of safety features in cars, such as airbags and crumple zones, which help to reduce the force exerted on passengers by increasing the time over which the force acts, thereby potentially saving lives.