In a crash test, a truck with a mass of 2500 kg traveling at 25 m/s smashes head-on into a concrete wall without rebounding. The front end crumples so much that the truck is 0.65 m shorter than before. What is the average speed of the truck during the collision (that is, during the interval between first contact with the wall and coming to a stop)? About how long does the collision last? What is the magnitude of the average force exerted by the wall on the truck during the collision? It is interesting to compare this force to the weight of the truck. Calculate the ratio of the force of the wall to the gravitational force mg on the truck. (This large ratio shows why a collision is so damaging.)
or... Change in momentum=Net Force times Change in Time
The Attempt at a Solution
I really have no idea where to start this problem...