Saturday, February 28, 2009 4:49:47 PM
actually the seatbelt does help. The seat belt doesn't stop you completely at first, it gives a little and even when it locks, the material is designed to stretch a little. This along with the air bag and the car crumple zones etc. increases the amount of time it takes for the person to slow down, thereby reducing the force on the person: (as you have stated) F= ma a= (v-u)/t
Therefore: F= m[(v-u)/t]
So the force on the body is less (and so organs would probably not be damaged so much)