Explain The Concept Of Density ?
One of the properties characteristic of every material is its density. We observe that a small piece of one material may be heavier than a much large piece of another material. The mass per unit volume of a substance is called its density p = m/V Units of density are determined by dividing the chosen unit of mass by the unit of volume, as kilogram per cubic meter, gram per cubic centimeter, or slug per cubic foot. It is sometimes helpful to use another quantity called weight-density, or weight per unit volume: D = W/V Since W = mg, we have a simple relation between density and weight-density: D = ρg Weight-density is commonly used when we are concerned with effects depending upon force, while density is used when mass is to be considered. Solids and liquids are only slightly compresses by even large stresses; hence their densities are almost constant under usual conditions. Gases are readily compressed; hence it is necessary to states the conditions under which the densities are measured.
