I have a question that needs solving please. I have a stand that has a forced oscillator on it. The oscillator can force the stand to move at different harmonics. On this stand is a rig that a spring is clamped rigidly onto. ( I will provide a simplified drawing.). The movement is detected by an interferometer. The calculated resonance frequency should be somewhere around 300htz; however, all sorts of weard data has been obtained. My question is that, in essence, we have a spring within a spring. I.e. the stand is one object of mass oscillating, of which there is a second massed spring object that is free to move as well. Given enough time, should BOTH springed objects move back and forth with the same frequency as the driving force, or is it possible for the frequencies to be different?