1. The problem statement, all variables and given/known data I am teaching a class where we are trying to find the K of I=1/2Kmr^2 from rolling a very thin cylinder down a ramp. 2. Relevant equations Linear Forces: mgsinθ-F(friction)=ma angular forces: τ=Iα where τ=F(friction)r, I=Kmr^2 and a=αr distance=1/2*a*t^2 since the initial velocity is 0 3. The attempt at a solution If you solve for F(friction) for both linear and angular forces you get Ia/r^2=mgsinθ-ma which gives a=gsinθ/(1+I/mr^2)=gsinθ/(1+k) If you solve for K you get K=gsinθ/a-1 Using the distance formula you get K=gsinθt^2/(2d)-1 We are running the lab using a video camera which allows us to time to the nearest .03 seconds and the distance measurements are within .005 meters but we are getting a K for a very thin cylinder manufactured on a 3-D printer of 1.2. I can't figure out how there is that much error in the lab so I assume I am leaving something out in my calculations. Any help would be appreciated.