The equation of single harmonic motion is x = A sin (T2πt), where A is amplitude and T is the time period of the motion. From the given figure, A = 1 and T = 8. Thus, x = sin (4πt) x = sin (tπ) The acceleration is a = dt2d2x = −1π2sin(4πt) At time t = 34 s , the acceleration is a = −16π2sin(4π×34) = - 323π2cm/s2