Haha well so I'm still plugging away.
Using hookes law of f = -kx, I can then look at f = ma and then have ma = -kx, rearranging it to get a = -kx/m, plugging things into get an acceleration of -3.27 m/s^2. The negative sign makes sense because since it is past equilibrium but not at the max...
so I found the frequency using T = 2pi*sqrt(m/k), then 1/T. So my frequency came out to being .91 Hz.
I'm still working on the equation of motion for the mass, the acceleration at +10 cm from equilibrium, and the period of an external force that would drive the system at resonance.
Any...
I thought about finding the speed and acceleration at +10 cm.
At this point Kinetic + Potential Spring energy has to be equal to .039 J. So I can do .5mv^2 +.5kx^2, plugging in the mass, spring constant, and distance to find the velocity of the mass which for kinetic and potential to equal...
So.. I have an ideal linear spring that streches 20 cm when a 40g mass is hung from it. The spring is then mounted horizontally on a frictionless surface (screams conservation of energy/momentum) and a 60g mass is attached to it. The 60g mass is then displaced 20cm from equilibrum and released...