[填空题]
A hollow cylinder (hoop) is rolling on a horizontalm0)ndb+gy lv. surface at speed v=3.3 rp e-f,cjnrv-blcw) *j 7l( e:$m/s$ 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