1.how does inertia affect a person who is not wearing a seatbelt during a collision?
2.how does kinetic energy affect the stopping distance of a vehicle traveling at 30 mph compared to the same vehicle traveling at 60 mph?
3.how does kinetic energy affect the stopping distance of a small vehicle compared to a large vehicle?
4.keeping in mind the kinetic energy of a moving vehicle, how can a driver best prepare to enter sharp curves in the roadway?
5.using information about natural laws, explain why some car crashes produce minor injuries and others produce catastrophic injuries.

1. during a collision, the person not wearing a seatbelt is already in motion. there is no outside force (the seatbelt) to stop this motion. 
2. Kinetic Energy = 0.5 * m * v^2  because velocity is a squared term, doubling the velocity actually quadruples the kinetic energy, making the stopping distance much much greater
3. by the same logic as above, mass is not a squared term, therefore doubling the mass will double the kinetic energy, increasing the stopping distance -- but by not as much as increasing the velocity.
4. because a driver cannot alter the mass of his vehicle, the best way to enter sharp curves would be decreasing velocity (speed)
5. there are many factors that determine the degree of damage (to humans and property in a crash), most notably the size of the vehicle(s) and velocity.