If I push an object such as a cylinder of wood along a flat table (flat face of cylinder in contact with the table) through it's center of mass, the friction or energy required is not dependent of the surface area the block makes with the table, Friction = μ N, correct? And the energy required = friction force x distance. However, if I now rotate the cylinder about the center of mass (axis of rotation normal to the table) then does the friction (and energy required to rotate the block) depend on the surface area of the block in contact with the table (block weight and coefficient of friction are constant)? Obviously the mathematics is going to be a lot more complicated for the rotating block but I suspect the diameter of the block will affect the friction and energy require to turn the block one revolution. Correct?