Hello, I am having trouble finding the A in this problem. I found T=1/2=.5, I found K =31.55n/m. I tried using the formula KA2=MV2+KX2 to find amplitude but ended up with A=0.0435m This just does'nt seem right . I used .05m for a value of X. Does anybody know what I am doing wrong? A 200 g mass attached to a horizontal spring oscillates at a frequency of 2.0 Hz. At one instant, the mass is at x=5.0cm and has Vx=.30 cm/s determine the period, Vmax, Amplitude, and the total energy.