1. The problem statement, all variables and given/known data A certain yo-yo can be modeled as a uniform cylindrical disk with mass M and radius R and a lightweight hub of radius ½R. A light string is wrapped around the hub. (a) First, the yo-yo is allowed to fall. Find the angular velocity of the yo-yo when the string has unwrapped a distance L. (b) Now, imagine that that you pull upward on the string such that the yo-yo remains in the same place. Find the angular velocity of the yo-yo when you have pulled the string upward a distance of L. (c) Explain in words why it makes sense that the answers to parts (a) and (b) are different. 2. Relevant equations K (total) = .5 * I (center of mass) *w^2 + .5MR^2 I cm for a uniform cylindrical hub = .5M(R^2 + (.5R)^2) 3. The attempt at a solution (A) K (total) = .5 * I (center of mass) *w^2 + .5MR^2 = MgL W^2 = MgL/ (.5 *I (cm) + .5MR^2) I cm for a uniform cylindrical hub = .5M(R^2 + (.5R)^2) So.. W^2 = MgL/(.5 * (.5M(R^2 + (.5R)^2) + .5MR^2) W^2 = MgL/(1/4Mr^2 + 1/16MR^2 + 1/2MR^2) W^2 = gL/(13/16R^2) Does that seem about right? (obviously need to make it the square root but just leaving it squared for now) (b) I assume I cannot use conservation of energy, so maybe I could solve this with the Work that is done? I dunno, I'm confused I guess I don't know where to begin Thanks for any help fellow physics buds!