The x-t graph of a particle undergoing simple harmonic motion is shown below.  The acceleration of the particle at t =43sec is

From the graph, time period, T = 8 sec.Equation of motion isx(cm)=(1cm)sin⁡2π8tv=π4cos⁡π4ta=−π42sin⁡π4t At t=43sec,a=−π216sin⁡π443=−332π2cm/s2.