How do i get the calculation for question (b) (i) and (ii)

In the 1980's, congress authorized the u. s. department of energy to build the wipp facility in the chicuahuan desert in new mexico. what is the purpose of wipp?

Consider a system to be two train cars traveling toward each other. what is the total momentum of the system before the train cars collide?   kg • what must the total momentum of the system be after the train cars collide?   kg •  

Which of these questions might a character ask if the conflict is man versus self? a. which path should i take to better myself? b. which boulder will be too heavy for me to carry? c. which friend is going to ditch me today? d. all of the above