[单选题]
A roller coaster starts wj0: 2obggsy16yan9 mrit2s xsk5,dkqo 4h a speed of 5.0 m/s at a point 45 m above the bottom of a dip (See Fig. 6-2). Neglect friction, what will be thed5oq4 sxs 2kk, speed of the roller coaster at the top of the next slope, which is 30 m above the bottom of the dip?