Question

What are the derived units for the density quantities​

Answer 1

Answer:

In the most general sense, density could be defined as quantity of material per unit volume.

In SI units this leads to the unambiguous specification of density as kilograms per cubic meter (kg/(m^3)) and would be referred to as a mass density. I am unaware of any special SI name for the unit of density.

The situation in what I will refer to as the English system is not as well defined. Density would usually be specified in units such as pounds per cubic inch or cubic foot. I would term this as a weight density, since usually when people think of pounds they are thinking of weight or force. The English system has its roots in antiquity, before most people understood the difference between mass and weight, so units of mass in the English system came along relatively late in the development of this so-called system of weights and measures. Mass units include the slug and the pound mass. In my view, having two different units for mass, particularly when one of them has the same name as the unit of force, just adds to the confusion. In the old days, when physics textbooks were written using English units, the slug was used as the unit of mass, and it’s the one that makes the most sense to me. Its relationship to the pound is analogous to the relationship between the kg and the N.