The figures below show snapshot (Figure 1) and history (Figure 2) graphs for a wave traveling on a string. The snapshot graph shows the wave at t = 0 s; the history graph shows the displacement of the point on the string at x = 1.5 cm, indicated by the dot in the snapshot graph. What is the velocity of the wave? Express your answer to two significant figures and include the appropriate units. Enter positive value if the wave is traveling in the positive x-direction and negative value if the wave is traveling in the negative x-direction.