Stress & Strain

Introduction
 

Stress and strain describe how materials respond when forces are applied. This topic introduces the concepts of tensile stress, tensile strain and Young modulus, allowing students to quantify the stiffness of materials and predict how they deform under load. Understanding stress-strain behaviour is essential in engineering and materials science, where selecting appropriate materials is critical for designing safe and efficient structures.
 

AQA A Level Physics Specification: 3.4.3.2 Stress, Strain and Young Modulus
 

What You Need to Know
 

• Define tensile stress and state its unit (Pa).

• Define tensile strain and recognise that it has no unit.

• Calculate tensile stress using force and cross-sectional area.

• Calculate tensile strain using extension and original length.

• Define Young modulus as the ratio of tensile stress to tensile strain.

• Understand that Young modulus is a measure of a material's stiffness.

• Interpret stress-strain graphs for different materials.

• Distinguish between elastic and plastic deformation.

• Solve quantitative problems involving stress, strain and Young modulus.
   

Downloadable Topic Pack
 

Stress and Strain Topic Pack Exam Questions and Answers
 

Related Topics
 

• Hooke's Law

• Density

• Forces

• Conservation of Energy

• Mechanical Properties of Materials