1. The problem statement, all variables and given/known data "A truck weighs four times as much as a car, If the truck coasts into the car at 12 km/h and they stick together, what is their final velocity." 2. Relevant equations Change in momentum a = change in momentum b OR m1v1 = m2v2 OR (delta)P system = 0 3. The attempt at a solution I HAVE NO IDEA. SRSLY.