Prestone Manning presses with his reforms against the current. To help him practice, the party whip comes up with a novel Prestone-Pressing-Training device which eventually has him pushing back against his own motion. Prestone, of mass m = 71 kg, is power hurtled by enthusiasts at a speed v along the horizontal frictionless portion of a strange blue slide until he reaches the semi-circular part of the slide. Much to his surprise the slide of mass M = 2 x m moves without friction along the orange horizontal surface that it is on as he goes up its curved part which is a semicircle of radius R = 5.00 m. At the top of the semicircle, he goes into a horizontal track (equipped with a spatial inverter to keep him up right) which is a part of the slide and keeps him from falling. He eventually is stopped, relative to the slide, by a super heavy-duty spring of spring constant k = 13 200 N/m that is firmly attached to the track. If Prestone barely makes it across the top of the semicircular path, what is his initial speed in m/s? M m O 12.9 O 18.6 O 14.6 O11.1 O 9.89