Question

1. Define mass density and specific weight.
2. Define specific volume.
3. Define specific gravity.

Answer 1

ANSWER :

1) MASS DENSITY () :

• Mass density (also known as specific mass) is defined as it is the mass per unit volume of substance or it is the ratio of mass of substance per unit  volume. It means that , the amount of mass (of a particular substance) contained in a unit volume.It is denoted by the symbol (rho).SI unit is Kg/m3. (Mass density of water is 1000 kg/m3 it means that 1000 kg mass of water contained in unit volume )
• Specific Weight ( ): The specific weight is defined as it the weight of substance per unit volume (KN /m3 ,SI unit). (for example ::The specific weight of water is (mass density x gravity) 1000 kg/m3 x 9.807 m/s2 = 9807 KN/m3)

2) SPECIFIC VOLUME :

• Specific volume is defined as it is the volume per unit mass of substance. It means that the number of cubic meters occupied by 1 Kg of particular substance.It is reciprocal of mass density . The SI unit is m3/kg.

3)SPECIFIC GRAVITY :

• Specific gravity is defined as it the ratio of density (mass per unit volume) of a substance to the density of standard substance (of a equal volume).
• Water is taken as the standard fluid for liquids and air is taken as the standard fulid for gases.
• The density of fluid can be calculated with the help of specific gravity . If we know the specific gravity of fluid then, density = specific gravity of fluid x density of water
• for example the density of meccury = specific gravity of meccury (13.6) x density of water 1000 = 13600 kg/m3