[填空题]
A hollow cylinder (hoop) is rolling on a horizontal surfac.,lpu; e:0xo)hwolxz0ku2ol e at speed v=3.3 3+t3* 6on lo0sdrqyr8; j megs$m/s$ when it reaches a 15 $^{\circ} $ incline. (a) How far up the incline will it go? $\approx$ m (round to one decimal place) (b) How long will it be on the incline before it arrives back at the bottom? s