Cars transfer in and out by new models being made and cars breaking down. For example when my mom got her first car she drove it for a while. But after time the car got used to much and started to break down. This is like the law of conservation of energy because the car didnt get destroyed only the energy got transferred. The energy of a used car could be transferred to a new car because of things like a car getting a new door. Cars can change, energy can change but the energy cant be destroyed.