1. The problem statement, all variables and given/known data A block of mass m is on a platform of mass M, supported by a vertical, massless spring with spring constant k. When the system is at rest, how much is the spring compressed? When the spring is pushed an extra distance x, what is the frequency of vertical oscillation? 2. Relevant equations F = -kx 3. The attempt at a solution For the first question, I set F = mg = -kx, where m = (M + m), and found x = (M+m)g/-k For the second part, I'm not sure how to set it up. I first thought that frequency is independent of amplitude, but I was told that I have to first write a new second law equation and then find an equation of motion.