밑줄 친 부분에 들어갈 말로 가장 적절한 것을 고르시오.As a rol… | [9급 지방직 영어] 22년 1회차 기출문제 상세 페이지

밑줄 친 부분에 들어갈 말로 가장 적절한 것을 고르시오.
As a roller coaster climbs the first lift hill of its track, it is building potential energy—the higher it gets above the earth, the stronger the pull of gravity will be. When the coaster crests the lift hill and begins its descent, its potential energy becomes kinetic energy, or the energy of movement. A common misperception is that a coaster loses energy along the track. An important law of physics, however, called the law of conservation of energy, is that energy can never be created nor destroyed. It simply changes from one form to another. Whenever a track rises back uphill, the cars’ momentum—their kinetic energy—will carry them upward, which builds potential energy, and roller coasters repeatedly convert potential energy to kinetic energy and back again. At the end of a ride, coaster cars are slowed down by brake mechanisms that create ______ between two surfaces. This motion makes them hot, meaning kinetic energy is changed to heat energy during braking. Riders may mistakenly think coasters lose energy at the end of the track, but the energy just changes to and from different forms.

gravity

friction

vacuum

acceleration

빈칸에는 "friction"(마찰)이 들어가야 한다.
빈칸은 브레이크 장치가 "between two surfaces"(두 표면 사이에) 만들어 내는 것이며, 뒤에서 "This motion makes them hot"(이 움직임이 그것들을 뜨겁게 한다)으로 운동 에너지가 열에너지로 바뀐다고 설명하므로 마찰이 알맞다.
"gravity"(중력)는 두 표면 사이에서 브레이크가 만들어 내는 것이 아니다.
"vacuum"(진공)은 열을 발생시켜 감속시키는 작용과 무관하다.
"acceleration"(가속)은 속도를 늦추는 브레이크의 기능과 반대다.