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Physics vocabulary · Motion and Forces

Mass

Meaning in physics, with examples

/mæs/nounCore term

In physics, mass means: The amount of matter in an object, which also measures how hard it is to change the object's motion. It is measured in kilograms (kg) and does not depend on location.

In Turkish: kütle

How it is used

Used in almost every mechanics equation, starting with F = ma. You say an object 'has a mass of 2 kg'. Physicists keep mass and weight apart: an astronaut's mass is the same on the Moon, but their weight is only about one sixth.

Example sentences

  1. The trolley has a mass of 1.5 kg, so we need a bigger force to get the same acceleration.

  2. Measure the mass of each sample on the digital balance and record it to two decimal places.

Common collocations

  • have a mass of
  • measure the mass
  • mass per unit volume
  • point mass
  • rest mass
  • weightThe force with which gravity pulls on an object. It equals mass times the gravitational field strength (W = mg), is measured in newtons and changes from planet to planet.
  • inertiaThe tendency of an object to resist any change in its motion, so it stays at rest or keeps moving with the same velocity. Objects with more mass have more inertia.
  • densityThe mass of a material per unit volume, found by dividing mass by volume. It is measured in kilograms per cubic metre (kg/m³) or grams per cubic centimetre (g/cm³).
  • forceA push or a pull that can change how an object moves or change its shape. It has both size and direction and is measured in newtons (N).
  • SI unitsThe international system of measurement units used in science, based on seven base units such as the metre, kilogram, second, ampere and kelvin. SI comes from the French 'Système international'.

More terms: Motion and Forces

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