① According to the topic, when t=0, point O vibrates along the positive direction of Y axis, and according to the waveform translation method, the wave propagates to the right, indicating that the vibration direction of point O at this moment is along the negative direction of Y axis;

② According to the question, the particle at x=2m reaches the peak at the 1 th. T= 12T and t = 0.4s are known.

It can be seen from the figure that λ=8m, then the wave velocity V = λ t = 20m/s..

Answer: ① At this time, the vibration direction of point O is along the negative direction of Y axis;

② The wave velocity is 20m/s. 。