I need to know part C of the question I don't understand how to find concerted potential energy to kinetic

3. At the county fair, a ride called the "Tornado" is a giant roller coaster that ascends a 41.1-m hill and then drops 23.2 m before ascending the next hill. The train of cars has a mass of 5136 kg. a) How much work is required to get an empty train of cars from the ground to the top of the first hill? b) What power must be generated to bring the train to the top of the first hill in 40.0 s? c)How much PE is converted into KE from the top of the first hill to the bottom of the 23.2-m drop