In 1920, after returning from Army service, he produced a successful model and in 1923 turned it over to the Northeast Electric Company of Rochester for development.
        
             
        
        
        
Answer:
The bottom of the sea is 25 m below sea level.
Explanation:
Given data
Mass = 6.1 × 

We know that Buoyant force on the tank is equal to gravity force of the tank.



1020 ×  = 6.1 ×
 = 6.1 × 
 = 598039.21
 = 598039.21 
We know that
 = W × L × H
 = W × L × H
598039.21 = 300 × 80 × H
H = 25 m
Therefore the bottom of the sea is 25 m below sea level.
 
        
             
        
        
        
Your answer is 632,100J which is Choice D