1.how does inertia affect a person who is not wearing a seatbelt during a collision?

They continue to the speed of the car, and they were not braced in and did not brace themselves, so they continue into the collision, whereas the seatbelts could've stopped them with the car, and the airbags could've stopped you from flying out of the wind shield, but if you took out the airbags, cause Race Car, or Weight Reduction. RIP my friend, you should've worn a seatbelt, you are dead, and you broke the law. so good luck if you do stay alive. and keep yo eyes on the road amigos.