A stationary boat in the ocean is experiencing waves from a

storm. The waves move at 59km/h and have a wavelength of 155m . The

boat is at the crest of a wave.How much time elapses until the boat

is first at the trough of a wave?

## Answer

iven data, Speed of wave, v 59 km/h Wavelength of wave, λ 155m Calculate the speed of wave in m/s v = 59% 1-1 m/s 18 -16.39 m/s Calculate the frequency of the wave Here, f is the frequency of wave Substitute the values in above expression 16.39 155 -0.106Hz Calculate the time-period of wave Here, T is time-period Substitute the values in the above equation 0.106 -9.43s

The distance between the crest and the trough of a water wave is half of the wavelength. Therefore, to time elapses will be half of the time-period of the wave. Here, t is the time elapses to reach the boat at the trough Substitute the value of T in the above equation. 9.43 -4.72 s Hence, the time elapsed to reach the boat at the trough is 4.72s