Density
Mass packed into a given volume.
\rho = \dfrac{m}{V}
1What it means
Density tells how heavy a material is for its size. Objects denser than water sink; less dense float. SI unit: kg/m³ (also g/cm³).
2Variables
| Symbol | Meaning |
|---|---|
| \rho | Density (kg/m³) |
| m | Mass (kg) |
| V | Volume (m³) |
3Worked examples
Example 1 Worked solution
Q. A 200 g block has a volume of 50 cm³. Find its density.
- ρ = m / V = 200 / 50.
✓ ρ = 4 g/cm³
4Where it's used
- ✦Identifying materials and checking purity.
- ✦Predicting whether an object floats or sinks.
5Tips & common mistakes
- !Keep mass and volume units consistent.
- !Density of water ≈ 1 g/cm³ = 1000 kg/m³.