Dead starts bursting new ones being born, maybe more dwarf planets
Beginning when the bottom of the object first touches the water,
and as it descends and more and more of it goes under, the
buoyant force on it increases during that time.
As soon as the object is completely underwater, it doesn't matter
how deep under it is, the buoyant force on it remains the same.
To solve this problem it is necessary to apply the concepts related to Newton's second law, the definition of density and the geometric relationships that allow us to find the volume of the figures presented.
For the particular case of the Cube with equal sides its volume is determined by


In the case of perforated material we have that its volume is given according to the cylindrical geometry, that is to say



In this way the net volume would be



We need to find the mass, but we have the Weight and Gravity so from Newton's second Law




PART A) From the relation of density as a unit of mass and volume we have to



PART B) To find the weight of the cube then we apply the ratio of



