[填空题]
A hollow cylinder (hoop) is rol(-q u(,ryxmx yh 6wdz)ling on a horizontal 6 mp30hpj7yipaz0ae (surface at speed v=3.3 $m/s$ 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