i am doing a roller coaster project, and the coaster i picked was the Medusa in Marine World Six Flags. Now, I need help with the reqirements.

Question

i am doing a roller coaster project, and the coaster i picked was the Medusa in Marine World Six Flags. Now, I need help with the reqirements.
We have to have at least 10 forces, and I have 9. I'm not too sure of what some of the forces are on a coaster. Any help would be great.

is a barrel roll on a coaster zero G?

Also, what would be mass? the people?

THANKS!