a little help please..?

Question

Object A is a cylinder with the density of 0.8g/cubic centimeter and Object B is a flat rectangular object with the density of 1.2 g/cubic centimeter.
What will happen when the objects are placed in a container of water (water temp. = 4 degrees celcius)??

(a) Both objets will sink.
(b) Both objects will float.
(c) Object A will float and object B will sink.
(d) Object B will float and object A will sink.

i think the answers is (d), but I'm not sure whether the density or the shape of an object determines weather objects float/sink.

Answer 1

The density of water is 1g/cubic centimeter. Anything with a density less than this will float, and anything with a greater density sinks.

Answer 2

Suppose that both A and B have the same volume, say, 1 cubic centimeter.

Let us immerse both the objects well into the water in the container.

Both objects displace one cubic centimeter volume of water.

The mass of displaced water is 1 g as the density of water is 1g/ cc.

This displaced mass of water pushes both the objects up with a force equivalent to its weight.

Since this upward force is more than the weight of A ( whose mass is 0.8g), it goes up to the water surface. And as it begins to emerge out of water surface the displaced water becomes less and the object begins to float when the two forces are equal and opposite.

But the object B sinks to the bottom as the weight of B is more than the weight due to the displaced water.