If a seagull sitting in water bobs up and down once every 2 seconds and the distance between two crests of the water wave is 3 m, what is the velocity of the wave?

1. 1.5 m/s
2. 3 m/s
3. 6 m/s
4. 12 m/s

A boat in the trough of a wave takes 3 seconds to reach the highest point of the wave. The velocity of the wave is 5 m/s. What is its wavelength?

1. 0.83 m
2. 15 m
3. 30 m
4. 180 m