[填空题]
A hollow cylinder (hoop) is rolling ovnuj8y uy9kh972vyh -n a horizontal surface at speed v=3e2cwcr2uz gagskbfp23vdc3 .+./ w w2.3 $m/s$ 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