1. The problem statement, all variables and given/known data There is a spring with 2 masses with a combined mass of 0.69kg. The vertical oscillation has a frequency of 1.5Hz. The amplitude of the oscillation is 30mm. Now this spring is attached to a horizontal support rod that can be made to oscillate vertically. how do i work out the phase difference with the driver (the spring)? 2. Relevant equations 3. The attempt at a solution If it oscillates with a frequency of 0.2Hz the amplitude will be less than resonance and there will be forced vibrations. , but how do i work out the phase difference with the driver (the spring)?