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Scalar and vector quantities - EdexcelScalar quantities

Scientists often make measurements. The physical quantities they measure fall into two categories: scalars and vectors. Scalar and vector quantities are treated differently in calculations.

Part of Physics (Single Science)Motion and forces

Scalar quantities

A physical quantity is something that can be measured. Scalar quantities only have a or size.

Learn more on scalar and vector quantities, contact and non-contact forces in this podcast

Examples of scalar quantities

Some examples of scalar quantities include:

  • temperature – eg 10 degrees Celsius (°C)
  • mass – eg 5 kilograms (kg)
  • energy – eg 2,000 joules (J)
  • distance – eg 19 metres (m)
  • speed – eg 8 metres per second (m/s)
  • density – eg 1,500 kilograms per metre cubed (kg/m3)

Calculations involving scalar quantities

Adding scalars

The sum of scalar quantities can be found by adding their values together.

Example

Calculate the total mass of a 75 kg climber carrying a 15 kg backpack.

75 kg + 15 kg = 90 kg

Subtracting scalars

Scalar quantities can be subtracted by subtracting one value from another.

Example

A room is heated from 12°C to 21°C using a heater. Calculate the increase in temperature.

21°C - 12°C = 9°C

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Vector quantities

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