Very large accelerations can injure the body, especially if they last for a considerable length of time. One model used to gauge the likelihood of injury is the severity index ( ???????? ), defined as ????????=????5/2???? . In the expression, ???? is the duration of the accleration, but ???? is not equal to the acceleration. Rather, ???? is a dimensionless constant that = the number of multiples of ???? that the acceleration is equal to.In one set of studies of rear-end collisions, a person's velocity increases by 13.7 km/h with an acceleration of 36.0 m/s2 . Let the +???? direction point in the direction the car is traveling. What is the severity index for the collision?