In a set up such as the following:
I have read in many places that below resonance the driving force is in phase with the harmonic oscillator. I have also read that the driving oscillator is in phase with the harmonic oscillator, however, I would not expect both to be true.
In a harmonic oscillator, I am under the impression that the acceleration (proportional to force) and the displacement are in antiphase. Therefore one would not expect the driving force and driving oscillator to be in phase.
I was wondering if the force acting on the driving force is not the same as the force it applies on the harmonic oscillator, and that perhaps the displacement and applied force of a driving oscillator are in fact in phase.
Is this correct, or do the two original statements, in fact, contradict each other?