How do I do this question?

Use the following information to answer the next question position marked B. The diagram below shows a roller coaster with a mass of 1500 kg. The roller coaster starts from rest at the B D E A h= 0m h= 0m h=90 m h=40 m h=80 m Numeric Response h 40m The speed of the roller coaster at position C is m/s 2 . (Record your answer in the numerical-response section on the answer sheet.)