A roller coaster starts at a point 30 m above the bottom of a dipwith a speed of 25 m/s. Neglect friction, what will be the speed of the roller coaster at the top of the next slope, which is 45m above the bottom of the dip?
A) 16 m/s
B) 18 m/s
C) 14 m/s
D) 20 m/s