Physical oceanography: Waves

[starfire123]

A former sea captain recounts a stormy night in Atlantic when he observed waves with wavelengths of a few metres passing his 51m long ship in less than 3s. Should you believe him?

How do we go about answering this question? I have no idea where to start from, well, we learned about group velocity and phase speed of waves, but I don't know how to use them to answer the question?

 

[SteamKing]

Think about the vessel heading into the wave. If the vessel had some speed on it, would the observation about the waves make sense?

 

[starfire123]

hm.. i think its possible? because waves can travel at a speed of 1m/s (assuming wavelength is 3m and period=3s?)

is tat the way to support the answer though? it seems too simple

 

[SteamKing]

Don't you know a formula for calculating the velocity of a deep water wave given the wavelength? Remember, deep water waves of a given wavelength all travel at a certain velocity relative to a fixed reference point. An observer on a vessel is not necessarily fixed in position relative to the wave motion.

 

[paranormal]

As a scientist, it is important to approach this scenario with a critical and analytical mindset. While the former sea captain's account may seem impressive and believable, it is important to gather more information and data before coming to a conclusion.

Firstly, it is important to understand the concept of wavelength and how it relates to waves. Wavelength is the distance between two consecutive points on a wave that are in phase, or have the same position in their respective cycles. In physical oceanography, we often measure wavelengths in meters.

Next, we need to consider the speed at which the waves were passing the ship. The former captain mentions that the waves had wavelengths of a few meters and were passing the 51m long ship in less than 3 seconds. This would mean that the waves had a speed of at least 17 meters per second (51m/3s).

Now, let's compare this speed to the typical speed of ocean waves. According to the National Ocean Service, the average speed of ocean waves is around 10 meters per second. This means that the waves the captain observed were moving significantly faster than the average ocean waves.

Additionally, we can use the equations for group velocity and phase speed to further analyze the situation. Group velocity is the speed at which a group of waves is moving, while phase speed is the speed at which an individual wave is moving. Without knowing the type of wave the captain observed, it is difficult to determine the specific values for group and phase velocity. However, based on the information provided, it is likely that the observed waves had a high group velocity and a shorter phase speed, which could explain why they were passing the ship at such a fast rate.

In conclusion, while the former sea captain's account may seem believable, it is important to approach it with a critical eye and gather more information before coming to a conclusion. The observed waves may have been unusual or extreme, but without further data and analysis, it is difficult to determine their exact nature. As scientists, it is important to gather evidence and consider all possible explanations before making a definitive judgement.