4 kilograms equals how many cubic feet?

Answer 1

This question cannot be answered sensibly. A cubic foot is a measure of volume, with dimensions [L3]. A kilogram is a measure of mass, with dimensions [M]. Basic dimensional analysis teaches that you cannot convert between measures with different dimensions such as these without additional information. It takes only a little mental effort to compare a cubic foot of air and a cubic foot of lead to see that the two will have very different masses.

Answer 2

4 kilograms is a measurement of weight, while cubic feet is a measurement of volume. To convert kilograms to cubic feet, you would need to know the density of the substance you are measuring. Without this information, a direct conversion from kilograms to cubic feet is not possible.