pauldw
Contributor
Heavier part is going to roll toward the bottom, right?
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If the cube is made of the same material, there is no ‘heavier/denser’ part.Heavier part is going to roll toward the bottom, right?
UniformIs the wooden cube of uniform density through its entire volume, or is there a knot or nail in it?
I gave you a hint: figure out why a log of uniform density floats horizonally.Heavier part is going to roll toward the bottom, right?
The center of gravity of the uniform cube is in the center of the cube. The center of gravity of the volume of displaced water (in the shape of a truncated cube, or square box shorter than the wooden cube) is in the center of that box. That point is directly under the center of gravity of the cube. So the face of the cube is the most stable position for the cube to float in.
The center of gravity of the displaced water is ALWAYS directly under the center of gravity of the cube, so this argument is mute. But you are thinking in the right direction, keep going!The center of gravity of the uniform cube is in the center of the cube. The center of gravity of the volume of displaced water (in the shape of a truncated cube, or square box shorter than the wooden cube) is in the center of that box. That point is directly under the center of gravity of the cube. So the face of the cube is the most stable position for the cube to float in.
I read the 1st reference, they are mostly wrong. First, their statement that "The centre of buoyancy is the centre point of the mass below the water and is the point through which the buoyant force acts" is wrong. The centre of buoyancy is the centre point of the volume below the water, because it is the centre point of the displaced water. This makes no difference for uniform objects but for non-uniform objects, like boats and buoys, the difference is significant. Second, for any uniform object, the centre of buoyancy can not be located above the object's mass centre, so their figures are wrong and most of their arguments are wrong.It’s late and I want you to get a good nights rest.
Flotation, centre of buoyancy
Stability in Flotation