What is the Stress Formula? (original) (raw)

Last Updated : 23 Jul, 2025

Stress is a key term in physics and engineering that defines the internal forces per unit area of a material caused by external loads. Understanding stress is vital for developing and assessing buildings, materials, and mechanical systems in many domains. The symbol for stress is σ and it is measured in N/m2. Learn more about Stress formula and examples based on them in this article.

Stress Definition

In physics and engineering, stress is defined as the internal force per unit area that acts on a material. It is a measure of the intensity of internal forces within a material that arise in reaction to external loads or applied forces. Stress denotes a material's deformation or shape change in response to external forces.

Stress Formula

Stress is equal to force acting per unit area. The stress formula can be defined as,

**σ = F / A

where,

• σ = Stress
• F = Force applied
• A = Area on the surface

Unit of Stress

The unit of stress is N/m2. The other unit of measurement for stress is Pascal, denoted as Pa. The commonly used units of stress are gigapascal, denoted as GPa, and megapascal, denoted as MPa.

Dimension of Stress

The dimension formula of stress is ML-1T-2

**Related Articles

• **Stress and Strain
• **Stress Strain Curve
• **Hooke's Law
• **Mechanical Properties of Solid

Solved Examples on Stress Formula

**Example 1: Find stress if a force of 40 N is acted upon an **object with area 4mm 2 .

**Solution:

Given,

• Force (F) = 40N
• Area (A) = 4mm2

According to the formula for stress,

**σ = F / A

σ = 40N / 4mm2

**σ = 10 ×10 6 **N/m 2

**Thus the stress on the surface is 10×10 6 N/m 2

**Example 2: Find the stress on a rubber band with an area of 0.35m 2 which is pulled with a force of 500 N.

**Solution:

Given,

• Force (F) = 500N
• Area (A) = 0.35mm2

According to the formula for stress,

**σ = F / A

σ = 600N / 0.3mm2

**σ = 2000 N/m 2

**Thus the stress on the surface is 2000 N/m 2

**Example 3: Find area if stress is 1000N/m 2 and force is 500 N.

**Solution:

Given,

• Stress (σ) = 1000N/m2
• Force (F) = 500 N

According to the formula for stress,

σ = F / A

Rearranging the formula for stress,

A = F / σ

A = 500/1000

**A = 0.5

**Thus area is 0.5 m 2

**Example 4: Find force if stress is 800N/m 2 and area of 0.2m 2 .

**Solution:

Given,

• Stress (σ) = 800N/m2
• Area (A) = 0.2 m2

According to the formula for stress,

σ = F / A

Rearranging the formula for stress,

F = σ×A

F = 800×0.2

**F = 160 N

**Thus force is 160 N.

Practice Questions on Stress Formula

Q1. A force of 800 N is applied to a steel rod with a cross-sectional area of 0.005m2. Calculate the tensile stress experienced by the rod.

Q2. A concrete column with a cross-sectional area of 0.2m2 experiences a compressive force of 500 kN. Determine the compressive stress exerted on the column.

Q3. A steel beam with a cross-sectional area of 0.01m2 is subjected to a bending moment of 10 kNm. Determine the bending stress experienced by the beam.

Q4. An aluminum wire with a cross-sectional area of 2mm2 experiences a tensile force of 50 N. Determine the tensile stress developed in the wire.