question: What can be used to stop trucks?
choices.text: water noise friction vibration magic fluid fire Chemicals
choices.label: A B C D E F G H
fact2: Brakes are applied to the rear wheels on No. 2 truck.
combinedfact: friction is used for stopping trucks
formatted_question: What can be used to stop trucks? (A) water (B) noise (C) friction (D) vibration (E) magic (F) fluid (G) fire (H) Chemicals