Stress
The restoring force per unit area developed inside a body when it is deformed by an external force.
What is Stress?
The internal restoring force per unit cross-sectional area of a deformed elastic body.
Key formula / rule: Stress
Key points
- Define stress and its physical significance.
- Understand the relationship between deforming force, area, and stress.
- Identify the SI unit of stress and other common units.
- Differentiate stress from applied force.
Common exam trap
Confusing stress with the applied force (F) instead of force per unit area.
Definitions
- Term
Stress
- Meaning
The internal restoring force per unit cross-sectional area of a deformed elastic body.
- Term
Pascal (Pa)
- Meaning
The SI unit of stress, equal to one Newton per square meter ($1 N/m2$).
Learning objectives
Define stress and its physical significance.
Understand the relationship between deforming force, area, and stress.
Identify the SI unit of stress and other common units.
Differentiate stress from applied force.
Formulae
- Name
Stress
- Note
F is the magnitude of the deforming force, A is the cross-sectional area.
- Expression
$\σ = F/A$
Prerequisites
Force
Area
Elasticity
Common mistakes
Confusing stress with the applied force (F) instead of force per unit area.
Using inconsistent units for force and area.
Assuming stress is always uniform across the area.
Keywords
Stress
Force
Area
Elasticity
Deformation
Restoring Force
Pascal
Practice preview
Which of the following is the SI unit of stress?…
easy
When a rod is subjected to a tensile force, the stress developed is known as:…
easy
Consider a cube of side 'a' subjected to a uniform pressure 'P' on all its faces. The stress developed within the cube is:…
medium