Hi guys so this is my first time posting a question on this amazing forum, i hope i am doing this right since i read that no one will help me if i am missing something. Anyways, i am dealing with a physics problem that it driving me crazy (mainly because my teacher does not explain anything!) Here is the problem. 1. The problem statement, all variables and given/known data An 7.50-cm-diameter, 320 g sphere is released from rest at the top of a 1.90-m-long, 20.0 incline. It rolls, without slipping, to the bottom. b. What fraction of its kinetic energy is rotational? So the known data is: mass= 0.0320 kg radius= 0.0375 m delta x= 1.90m wi = 0 vf = 3.02 m/s wf = 80.5 rad/s Find ratio between rotational and kinectic energies. 2. Relevant equations Kroll = 1/2 (I* w^2) + 1/2(M)(vf)^2 = Krot + Kcm 3. The attempt at a solution ok so from part A of the problem i found the velocity at the bottom of the incline to be 3.02 m/s, then i found the final angular velocity. With that all i thought i had to do was plug the data into the previous equation and get an answer: Since moment of inertia of a cylinder is 2/5MR^2 Kroll = 1/2 (2/5 ) (0.032kg)(0.0375m)^2 ( 80.5 rad/s)^2 + 1/2 ( 0.032 kg)(3.02 m/s)^2 I am getting 0.204 for the Kroll and for the Krot i am getting 0.06... when i devide 0.06/0.204 i get 0.3 which is not the answer :( i have no idea what am i doing wrong! please help me, this homework was due 2 days ago, i am just doing it to understand the concept no for the points, so i would really appreciate your help, wonderful people, thanks!