The density is defined as mass per unit volume. The density is denoted by ρ (Rho)
So mathematically we can write density,
Density (ρ) = mass (m)/volume (v)
ρ = m/v ——- (i)
Where, ρ is density
m is mass
v is volume
The density of material varies with temperature and pressure. The unit of mass is kg and unit of volume is m3 so, SI unit of density (ρ) is kg 1m3. From above formula we can calculate density of material. Density is measure of how a material is tightly pack together. It the material is heavy or hard then this called dense material. Because in solid particular is closely packed. In liquid the particles can slide around one another, & in gases particles are freely move. So liquid are less dense than solid and gases are less dense than liquids.
Numericals on Density:
Question 1:
If the mass of water 1220 kg and a volume of 2 m3 then calculate the density of water?
Given:
Mass = 1220 kg
Volume = 2 m3
Density = Mass/volume
= 1220/2 = 610 kg/m3
Question 2:
Mass of wooden block 500 kg, if the density of wood is 0.3 g cm-3. Calculate the volume of wooden block?
Given:
Mass of wooden block (M) = 500 kg
Density (ρ) = 0.03 g cm-3
ρ = 0.3 g/cm3 = 0.3 × 1000 = 300 kg/m3
Volume =?
ρ = m/v
∴ V = m/ ρ = 500/300
V = 1.6 m3
Volume of block is 1.6 m3