Contents and methods of law: 1. Rotate the law of production relations in accordance with the level and nature of production development
2. The law of the dialectical relationship between infrastructure and superstructure

Arailroad car collides with and sticks to an identical railroad car that is initially at rest. after the collision, the total kinetic energy of the two cars is a) the same as before. b) half as much as before. c) one third as much as before. d) one fourth as much as before. e) twice as much as before.