Answer:
The value is 
Explanation:
From the question we are told that
The first amplitude of the wave is 
The first depth is 
The second amplitude is
The second depth is 
Generally from the spatial wave equation we have

=> 
So considering the ratio of the equation for the two depth

=> 
=> 
=> 
W =F triangle d cosine0. F = 25 Newton’s. Delta d = 50 meters. Theta =40.0 degrees