Mass

Mass is, informally, the amount of material in an object. It is one of the core concepts of physics, especially mechanics.

Formal Definition

Mass is a measure of the amount of matter a physical body contains. Mass is often confused with weight, but is not the same. While weight is a measure of the gravity on a body, mass is the amount of matter. Note that in a standard gravitational field, mass is directly proportional to weight.

Units of Measure

• The SI unit for mass is the gram.
• Larger units include the kilogram (1000 grams), tonne (1000 kilograms), kilotonne (1000 tonnes), megatonne (1000 kilotonnes), etc.
• The imperial system has no measure for mass, as at the time it was popularized, the distinction between mass and weight had not been popularized.

Related Formulae

• Momentum is calculated by , where is momentum, is mass, and is velocity.
• Thermal energy is calculated by , where is the thermal energy, is mass, and is heat.

See Also

• Weight
• Gram