The crests of an ocean wave are 10.0 m apart, and a floating gull takes 5.00 s to bob up and down once. What is the wave velocity?

1. The distance between adjacent crests is the wavelength, so wavelength = 10.0 m. 2. The time for the gull to bob up and down once is the period, so T = 5.00 s. 3. Wave velocity is v_w = wavelength / T. 4. v_w = 10.0 m / 5.00 s = 2.00 m/s. 5. Multiplying instead of dividing gives 50.0 m/s, far too fast for an ocean swell. 6. This is the speed of the disturbance along the surface, not the speed at which the gull rises and falls. _Source: OpenStax College Physics (CC BY 4.0), Ch 16 "Oscillatory Motion and Waves", section 16.9 Waves_