Length of the pendulum (l) = 2 m
Acceleration due to gravity = g = 9.8 m/s^2
For small amplitude, the pendulum will undergo simple harmonic motion.
Hence, the time period of the pendulum for small amplitude = 
Now, plug the values of l and g
T = 
T = 2 × 3.14 × 0.451
T = 2.83 seconds
Hence, the time period of the pendulum for small amplitude = 2.83 s
Well, he was falling at 78 m/s, assuming

and the air friction is negligible.
Sorry I don't know this but my guess it water in the storm or the other way around.
<u>Answer</u>
Another wave
<u>Explanation</u>
Diffraction is the is the change of direction of a wave due to an obstacle or an opening in the media. It results in to a disturbance.
It occurs when a wave goes through a gap or meets a barrier in a media such as a small island, a large ship or a protruding rock.
The correct answer is another ship.
The answer is here just click it you won’t regret it. You’ll laugh
https://youtu.be/dQw4w9WgXcQ