Explanation:
Equilibrium position in y direction:
W = Fb (Weight of the block is equal to buoyant force)
m*g = V*p*g
V under water = A*h
hence,
m = A*h*p
Using Newton 2nd Law

Hence, T time period
T = 2*pi*sqrt ( h / g )
Answer:
g = 5 m/s square
Explanation:
Weight(W), Mass(m), Gravity(g)
W = mg
1,000N = 200g
g = 1000/200
g = 5 m/s square
I think its Mercury because it's the closest to the sun.