On Earth a 100 kg person riding a 300-meter-high roller coaster has 300 kj of potential energy at the top of the roller coaster. The Moon has roughly 1/6 the gravity of Earth. How high would a roller coaster need to be on the Moon so that a 100 kg person had 300 kj of potential energy at the top of the roller coaster? A. 300 meters

B. 50 meters

C. 1,800 meters

D. 600 meters