1. The problem statement, all variables and given/known data "A mass stands on a platform which executes simple harmonic oscillation in a vertical direction at a frequency of 5 Hz. Show that the mass loses contact with the platform when the displacement exceeds 10^-2 m." 2. Relevant equations x(t) = a cos(wt - phi) frequecy = 1/T = w/2(pi) 3. The attempt at a solution Ok, so I solved for w: 5 = w/(2 * pi) w = 31.41592 rad/s But the thing is, I don't understand the fundamentals of this question, how can a mass stay on a platform without gravity pushing it against the board? I.E. What am I solving for? I'm guessing there's a threshold somewhere to solve for but I'm just not seeing it. I.E. if the question specified a mass and gravity constant I could use that as the force holding the mass on the platform and when the platform's force exceeded the force of gravity the mass would lose contact - but I don't have that here. I'm utterly confused.