[填空题]
A hollow cylinder (hoop) ek v i6 nzvtix*-;c*23bf2oj .i xu3opis rolling on a horizontal surf.zrgp8hsw8n;h jv ez5 ,em, 9edg e-+face 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