A particle is performing simple harmonic motion along x-axis with amplitude 4 cm and time period 1.2 sec. The minimum time taken by the particle to move from x =2 cm to x = + 4 cm  and back again is given by

Time taken by particle to move from x=0 (mean position) to x = 4 (extreme position) =T4=1.24=0.3 sLet t be the time taken by the particle to move from x=0 to x=2 cm  y=asinωt⇒2=4sin2πTt⇒12=sin2π1.2t⇒π6=2π1.2t⇒t=0.1 s. Hence time to move from x = 2 to x = 4 will be equal to 0.3 – 0.1 = 0.2 sHence total time to move from x = 2 to x = 4 and back again =2×0.2=0.4sec