A cylinder like an oil drum is being rolled across a level floor by a force ~F applied horizontally to the top. For the cylinder of mass M and radius R, Icm = (kappa)M R2. The center-of-mass acceleration of the cylinder entirely in terms of F, kappa, and M, where F is the magnitude of ~F is aCM=2F/(k+1)M. The cylinder does not slip as it rolls. What is the force of friction between the cylinder and the floor in terms of only F and kappa?