A rear-facing child safety seat holds a child of mass 12. kg rigidly within the 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’s crumple zone causes the distance traveled by the rigid interior to be 1.0 m. Give the stress experienced by the child’s body in terms of a fraction of the breaking strength of bone, assuming an infant’s bones break at a stress of 10. MN/m².

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