Recently, I have done an experiment of frictional on rolling object. In the experiment, I have done 7 trials with different axle radii, similar to that of a yoyo on a horizontal table. the experimental was set as this As derived by the lab manual i received, frictional force can be plotted as a function of axle radius. f=2mgMR(R-2r)/(3MR^2+4m(R+r)^2) The graph plotted using my experimental data is very strange....... Both graphs are plotted by f as a function of r. The one on the right is plotted according to my experimental data. The one on the left is a plot of the equation above. Why the graphs are so different? Is there anything wrong?