I'm not 100% sure, but I believe what you mean is when they eject the old propulsion motors. Yes, they land in the ocean and the US Navy retrieves them for later use.
Answer:


Explanation:
r = Radius = 2.7 cm
F = Force = 
A = Area = 
= Stress = 
E = Young's modulus = 
= Strain
= Original length = 67 cm
= Change in length
Young's modulus is given by

Strain is 
Strain is given by

The cylinder height decreases by 
Yes. Your answer is correct. I hope you do well on the quiz or whatever it is.
It is -59 i think or just ask someone esle for help