A mass is vibrating at the end of a spring of force constant 225 N/m. On a position x vs time graph, how do you determine:

How much energy did this system originally contain?

1 answer

The maximum stored energy is
E = (1/2)k(Amplitude)^2
The Amplitude is the maximum displacement from the average position during vibration. They told you what the spring or "Force" constant k is.