Thanks for looking into my thread. I find various threads suggest to use Kinetic energy/conservation of momentum to explain car collision. Moving car generate/carry more energy compared to stopped one. I find when a car (car1) (moves with 10-15 miles/hr) rear-ends stopped vehicle (car 2), the stopped car (car2) sustain more damage compare to moving one (car1) . Car 1 has kinetic energy and car 2 has 0 kinetic energy. Does the Kinetic energy of car 1 contribute for more damage to car 2? Is there a way to explain the above situation using physics? Thanks for your guidance.