Sorry, the title is wrong, it's hoop rolling UP an incline 1. The problem statement, all variables and given/known data In a circus performance, a large 3.8 kg hoop with a radius of 1.8 m rolls without slipping. If the hoop is given an angular speed of 5.5 rad/s while rolling on the horizontal and is allowed to roll up a ramp inclined at 17◦ with the horizontal, how far (measured along the incline) does the hoop roll? The acceleration of gravity is 9.81 m/s2 . Answer in units of m. Known variables: M=3.8 kg R=1.8 m wi = 5.5 rad/s wf=0 rad/s vi= wR Angle A=17 degrees h= d*sin(A) d=? *im using v and w at the center of mass, same for inertia 2. Relevant equations I = MR^2 rotational KE= (1/2)Iw^2 + (1/2)Mv^2 3. The attempt at a solution KEf + Uf = KEi + Ui 0 + Mgh = (1/2)Iw^2 + (1/2)Mv^2 + 0 Mgh = (1/2)Iw^2 + (1/2)Mv^2 substitute: h=d*sin(A) w= v/R I=MR^2 Mgd*sin(A) = (1/2)(MR^2)(v^2 / R^2) + (1/2)Mv^2 Mgd*sin(A) = (1/2)Mv^2 + (1/2) Mv^2 Mgd*sin(A) = Mv^2 d = v^2 / (g*sin(A)) using v=wR = 9.9 d= 234.17 Which is wrong. I wasn't sure if i was supposed to include friction, does it even make sense for an object to roll without friction? i'm not sure, and i'm not sure how to even do the problem with friction. that would mean i would have to use torque right? Thanks for the help.