CIE IGCSE Maths

Revision Notes

7.1.2 Vectors - Modulus

What is a vector?

Vec Mod Notes fig1, downloadable IGCSE & GCSE Maths revision notes

 

  • Vectors have various uses in mathematics
    • In mechanics vectors represent velocity, acceleration and forces
    • At IGCSE vectors are used in geometry – eg. translation
    • Ensure you are familiar with the Revision Notes Vectors – Basics
  • Vectors have magnitude and direction
    • These notes look at finding the magnitude, or modulus, of a vector
    • Vectors are given in column vector form

What is the magnitude or modulus of a vector?

Vec Mod Notes fig2, downloadable IGCSE & GCSE Maths revision notes

 

  • This depends on the use of the vector
    • For velocity, magnitude would be speed
    • For a force, magnitude would be the strength of the force (in Newtons)
  • The words magnitude and modulus mean the same thing with vectors
  • In geometry magnitude and modulus mean the distance of the vector
    • This is always a positive value
    • The direction of the vector is irrelevant
  • Magnitude or modulus is indicated by vertical lines
    • |a| would mean the magnitude of vector a

How do I find the magnitude or modulus of a vector

  • Pythagoras’ Theorem!

 

Vec Mod Notes fig3, downloadable IGCSE & GCSE Maths revision notes

Exam Tip

Sketch a vector to help, it does not have to be to scale, then you can use this to form a right-angled triangle.

Worked Example

Vec Mod Example fig1 sol, downloadable IGCSE & GCSE Maths revision notes

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