its 4 a skool project due tmro

and we made 3-d models of roler coasters
let me tell u about mine

-theres 3 carts
cart #1 is- on a flat part of the track but about to go up a hill and came out of a tunnel a lil b4

cart#2 is- on a flat surface ready to turn

cart #3 is- just starting to go down a hill and into a tunnel (the tunnel is in water))
defination: (i got out of my science book))
The total momentum of any group of objects remains the same unless an outside force acts on the objects. .

so tell me ware on my roller coaster would demonstaright that?
use cart numbers pllz help me!!!
(theres also anoth tunnel some ware with no water))
wod the roller coaster going up (about to)
or just came up

either #1 or #2

being pulled up..wod that be an example!!?!