1. The problem statement, all variables and given/known data In a crash test, a truck with mass 2000 kg traveling at 23 m/s smashes head-on into a concrete wall without rebounding. The front end crumples so much that the truck is 0.67 m shorter than before. 2. Relevant equations About how long does the collision last? (That is, how long is the interval between first contact with the wall and coming to a stop?) Δt = (c) What is the magnitude of the average force exerted by the wall on the truck during the collision? Fwall, avg = N (d) 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. [Fwall, avg]/mg = 3. The attempt at a solution Well I figured out that the Average velocity during the collision was 11.5 m/s. But after this I am stuck.