Fundamental Units (OCR AS Maths: Mechanics)

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Fundamental Units

What are fundamental units?

  • Fundamental units or S.I. units are the international standardised units used around the world
  • The three main units you will be using are:
    • Length measured in metres (m) (also called displacement)
      • 1 km = 1000 m, 1 m = 100 cm, 1 cm = 10 mm

    • Time measured in seconds (s)
      • 1 hour = 60 minutes, 1 minute = 60 seconds

    • Mass measured in kilograms (kg)
      • 1 kg = 1000 g, 1 g = 1000 mg

  • All other quantities can be measured in units derived from S.I. units

Worked example

1-1-2-worked-solution_1

Examiner Tip

  • Make sure you fully understand the definitions of all the words in this section so that you can be clear about what your exam question is asking of you.
  • Make sure you are confident converting between fundamental S.I Units

    e.g.    17 minutes and 42 seconds = 1062 seconds

 2.4 km = 2400 m

 86000 mg = 0.086 kg.

  • Watch out for exam questions using non S.I. units such as feet and inches or miles per hour.
  • Remember mass (measured in kg) is not a weight (a force measured in Newtons).

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Amber

Author: Amber

Expertise: Maths

Amber gained a first class degree in Mathematics & Meteorology from the University of Reading before training to become a teacher. She is passionate about teaching, having spent 8 years teaching GCSE and A Level Mathematics both in the UK and internationally. Amber loves creating bright and informative resources to help students reach their potential.