1. The problem statement, all variables and given/known data 2. Relevant equations rBA= rA-rB UBA= rBA/rBA F= KS F= Magnitude of force S=Spring deformation >Lf-Li 3. The attempt at a solution So far I have found the components for RB and some RA, but the thing I'm missing is the R AZ. I know that at 0 and 90 degree the spring is 15 in because the spring was not stretch. I'm confuse on how to calculate the length of the spring when the disk turn and the angle increase. Thanks you so much in advance.