The density of an object depends on its mass and volume. There is some confusingly presented information about the volume but absolutely no information on the mass. It is, therefore, impossible to provide a sensible answer.
A rectangular prism or a cuboid.
Dome
Another cylinder
Rectangular prism
No it will not change. Density is mass divided by volume. Since the ratio of the mass is 1/2 and the volume ratio is 1/2, there is no change. The same holds true no matter how you cut the block, as both mass and volume change proportionally the same.
A rectangular prism or a cuboid.
If a solid block of material is cut in half, its density remains the same. Density is a physical property of a substance and is independent of the shape or size of the object. Therefore, cutting the block in half would not change its density.
The density of the solid substance remains unchanged when it is cut in half. The mass and volume are both halved, which means the ratio of mass to volume, i.e., density, stays the same.
If you were to cut a cube in half along any plane passing through its center, you would get two equal halves of a cube. Each half would still have the shape of a cube with the same dimensions, just split into two separate pieces. The resulting solid figures would be two smaller cubes.
The density does not change, as density is the amount of material in a given amount of space. But each piece has the same amount of space and material relative to each other.
The density of each half remains the same as the original density of the bar. Cutting the aluminum bar in half does not change the density of the material, as density is an intrinsic property of the material.
two rectangular prisms but they are smaller
If the mass of a substance is cut in half but the volume remains the same, the density of the substance would also be cut in half. This is because density is calculated by dividing mass by volume, so reducing the mass will directly affect the density without changing the volume.
Dome
If the density of an object is cut in half while its mass remains constant, its volume would double. This means the object would expand or increase in size to occupy a larger space in order to achieve the lower density.
A small rectangular box!
Another cylinder