Mass doesn't change, no matter where you take it.
Your first impression of ' 0 ' is totally correct.
Answer:
The spring constant is 3750 N/m
Explanation:
Use the following two relationships:
(Work) = (Force) x (Displacement)
(Force) = (Spring constant) x (Displacement)
=>
(Spring constant) = (Force) / (Displacement) = (Work) / (Displacement)^2
(Spring constant) = 6.0 kg.(m^2/s^2) / 0.0016 m^2 = 3750 N/m
The spring constant is 3750 N/m
The buoyant force must be greater than water.
