Question

Many automobile passengers have suffered neck injuries when struck by cars from behind. How does Newton's law of inertia apply here?

Answer 1

The body is resisting the stopping motion; it wants to continue moving based on Newton's laws.

↑↑↑ Hope this helps :D

Answer 2

Newton's law applies here because an object in motion (your body) stays the speed that you were going, so if you were hit, your body would keep going when the car is stopped. This causes your body (especially your neck) to whip back and possible break.