Physics

• Mass : is the amount of matter in a certain object
• Density : is the mass per unit volume
• the mass of objects can be measured by two balance : equal arm balance , digital balance
• S.I unit of mass is : KG
• Density of a substance is the ratio of the mass of this substance to its volume
• SI unit of density : kg/m^3
• What is density mostly used for : Density is mainly used to identify pure substances
• Density = mass (kg) volume (m^3)
• Define density : density of a substance, is the ratio of the mass of the substance to its volume