A rear-facing child safety seat holds a child of mass 25. kg rigidly within the rigid interior of a car. The area of contact between the seat and the child is 0.10 m². The car undergoes a 30. mph collision. The car has no crumple zone, but a harness attached to the car seat stops it uniformly within a distance of 0.30 m. According to the Gadd severity index, will the child sustain serious injury or death?

Above exercise concern an infant’s rear-facing safety seat as illustrated here.