Displacement versus time curve for a particle executing S.H.M. is shown in Fig. 14.7. Identify the points marked at which (i) velocity of the oscillator is zero, (ii) speed of the oscillator is maximum.

The maximum velocity is always at the mean position of the SHM where displacement is zero

Thus, we can say that points B, D, F, H are the points where the velocity is maximum.

The minimum velocity is always at the points where the displacement is always maximum.

Thus points A, C, E, G are the points of where velocity is zero.