Help with the test please

Two carts, one of mass 2m and one of mass m, approach each other with the same speed, v. when the carts collide, they hook together. assume that positive momentum is to the right. which graph best represents the momentum of both carts over time, before and after the collision?

The ability to make things happen is also called a. heat b. force c. matter d. energy

Plz explain what friction, corollas, and a low pressure gradient does to an air parcel. what is 1+1=