Kinetic Energy would have to be the answer. Pretty sure.
Assuming the driver starts slamming the brakes immediately, the car moves by uniformly decelerated motion, so we can use the following relationship

(1)
where
a is the deleceration
S is the distance covered after a time t

is the velocity at time t

is the initial speed of the car
The accident is 80 m ahead of the car, so the minimum deceleration required to avoid the accident is the value of a such that S=80 m and

(the car should stop exactly at S=80 m to avoid the accident). Using these data, we can solve the equation (1) to find a:

And the negative sign means it is a deceleration.
Academic- affect on substances, how it works
Scientific- helping cancer, making weapons
The answer is 1.52.
N = C (speed of light) / actual speed
n = index of refraction