[填空题]
A hollow cylinder (hoop) is rolling on a horizonfp.c8 av swl.wo6 ina0w2)pe1tal surface at 7y6uftm ovk,2hddp 1(vom z54speed 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