Answer:
Step-by-step explanation:
A seatbelt is designed to stretch a bit when the car decelerates rapidly. You travel forward a little while being stopped - you do not stop sharply as you would if you hit the dashboard. The seatbelt stretching increases the time over which your momentum is changed, thereby decreasing the force experienced by your body.
Airbags are made from a strong coated fabric. They are stored in a module mounted on the steering wheel and dashboard and side panels of the car. The inflation of them is initiated by crash sensors that activate upon impact at speeds of more than 10-15 miles per hour. They are mounted in several locations on the car body. In a crash, the sensor sends an electrical signal to the airbag which then causes the airbag to deploy. It ignites a chemical propellant which produces nitrogen gas, which then inflates the bag itself.