Hello all. I'm a newer engineer in rotor dynamics trying to better understand some things, so perhaps someone can provide some insight... First, I'm trying to better understand the physics of forced, non-centroidal rotation (for a spinning cylinder in particular). Non-centroidal rotation requires some kind of constraint on a object to hold it to a certain axis, or else the object would naturally tend to rotate about its center of mass. Can this natural tendency (aka conservation of angular momentum) be represented via the principal of least action? Or is there another simple quantitative way of representing this, other than just declaring it so? And at the same time, could the same principal or technique then be used to calculate the net force or energy required to constrain such a rotating cylinder to some other rotational axis at some given speed? And also, to find the total torque required to spin the off-center cylinder up to a given speed (versus if the cylinder were rotating about its center of mass axis)? And, would the force required by the constraint be equivalent to the centrifugal force (m*e*omega^2) generated by the now-eccentric portion of the cylinder's mass? Thanks for your thoughts.