A fisherman notices that his boat is moving up and down periodically without any horizontal motion, owing to waves on the surface of the water. It takes a time of 2.20 s for the boat to travel from its highest point to its lowest, a total distance of 0.690 m . The fisherman sees that the wave crests are spaced a horizontal distance of 6.50 m apart. How fast are the waves traveling?

1.48 m/s

Explanation:

If it takes a time of 2.20 s for the boat to travel from its highest point to its lowest, then the period for the boat to travel from its highest point back to its highest point again is twice that, which is 2.2 * 2 = 4.4 s

Since wave crests are spaced a horizontal distance of 6.50 m apart, we can calculate the speed that waves are traveling at

6.5 / 4.4 = 1.48 m/s