Stress in Physics Overview
Stress is aphysical term that describes the amount of force applied to a material per square inch. Stress, which results from externally applied forces, is aphysical science andengineering term forforce per unit area within the material. The breaking stress, also known as theultimate tensile stress, is thehighest stress a material can withstand before breaking.Tension is whatcauses a substance to be tensile. The material is attempting to be stretched by the forces at work. There is an internal restoring force produced when the elastic bodies take on their original form. The restoring force is stress if we attempt to calculate how much it exerts per unit area on the deformed body.Compression occurs when a body is beingsqueezed by external forces.
What is Stress?
An item deforms when the deforming force is applied to it. Anopposing force will be producedinside the item to return it to its original size and shape. This restoring force will have the same magnitude as the applied deforming force and will be applied in the opposite direction. Stress is a term used to describehow much of this restorative force is produced per unit area of the material. Thus,"The restoring force per unit area of the material" is the definition of stress. It has a tensor value and is represented by the Greek lettersigma (𝝈). measured inN/m²or Pascal. Presented mathematically as -
𝞼 = F/A
The restoring force, or F, is expressed in Newtons or N.
A represents the cross-sectional area in m².
The stress is calculated using either N/m² or Pa.
Real-Life Stress Examples
Several examples of how stress is used in our daily lives are as follows-
- Everything from the foundations to the support beams to the columns incorporates the notion of stress and how it impacts the various components of the structure.
- The concept of stress is used in architecture to plan the construction of a building.
- The concept of stress is utilized to create numerous day-to-day tools that we use in our everyday lives, etc.
- The notion of stress is employed in the design of automobiles, spaceships, airplanes, and fighter planes, among other things.
Read more about theCohesive Forces,Frictional Force, andLorentz Force.
Highlights of Stress in Physics
The following table gives details about the stress in physics-
Details | Particulars |
Common Symbols | 𝞼 |
Other Units | Psi, bsr |
SI Unit | Pascal |
In SI base units | Pa = kg⋅m−1⋅s−² |
Dimension | L-1 MT−² |
History of Stress in Physics
Since the beginning of time, humans have been aware of internal tension in materials. This understanding wasprimarily intuitive and empirical up until the 17th century, but this did not stop the creation of highly sophisticated technologies like composite bow and glass making. With clever devices like thecapitals, arches, domes, trusses, and flying buttresses of Gothic cathedrals, architects, and builders, in particular, have learned over many millennia how to assemble carefullyshaped wood beams and stone blocks to withstand, transmit, and distribute stress in the most effective way.
Stress Units in Physics
Given that pressure is a dimension of stress, the coordinates ofstress are measured in pascals(Pa, or newtons per square meter) in theinternational system or pounds per squareinch (psi) in the imperial system. The unit ofmechanical stress known as MPa, ormegapascal, is frequently used because mechanical stresses frequently reach one million Pascals.Multiple units can be used to describe stress. The table below contains the stress units-
System of Units | Stress Units |
Fundamental units | Kg.m−¹.s−² |
SI (derived units) | N.m2 |
Pa or pascal | |
SI (mm) (derived units) | M.Pa or N/(mm)² |
US unit (ft) | lbf/ft² |
US unit (inch) | Psi (lbf/inch²) |
Types of Stress in Physics
Although there are many different kinds of stress in physics, they are primarily divided into two types:Normal Stress and Tangential or Shearing Stress. The following are a few different forms of stress-
Normal Stress
The normal force is thestress that results from applying an axial force to a component. To put it another way, when the stress applied to the body is perpendicular. The object's stress level returns to normal when its length and volume are changed. It stands in for the sign. In the SI system,normal stress is measured in millipascals (MPa).
Formula of Normal Stress
Normal Stress = Axial Force / Cross-sectional Area
Normal stress arises when an item is in tension or compression. Normal stress is further divided into two categories-
Particulars | Bulk Stress | Longitudinal Stress |
Definitions | Bulk stress isanother name for volume stress. The phrase "volume stress" refers tostress that creates fluctuations in the body's volume. Normal stress results in achange in length orvolume, whereas tangential stress results in a change in body form, which is referred to as volume stress. When a body is immersed in a liquid and subjected to the force of pressure p, it meets a force perpendicular to the body's surface. | Longitudinal stressoccurs when the length of the body varies as a result of normal stress. Longitudinal stress is the stretching or compressing of an item throughout its whole length. |
Formula | Volume Stress = Force / Area | Longitudinal Stress = Deforming Force / Cross-Sectional Area |
Types | - | As a result, it may be classified into two categories based on the direction of the deforming force - Tensile and compressive stresses |
Longitudinal Stress is further divided into 2 types-
Compression Tension | Tensile Strength |
When a tangential force is applied to a body, itchanges its form and volume. Once a compression load is applied, the length of the body is shortened. Tensile and compression stress are diametrically opposite forces. When you squeeze a pet's squeaking toy in your hand, you produce compression tension. | Tensile stress is stress that happens when adeforming force or applied force produces an increase in the length of an item. When you stretch a rod or wire, for example, equal and opposing forces (outwards) are exerted at both ends. |
Shearing stress or tangential stress
Shearing stress or tangential stress is defined as a force applied tangentially over the surface area of a plane. The surface is considered to be tangent when the forces acting on it are parallel to it and the stress acting on it follows a tangent. This sort of worry is known as shearing stress.
Stress Formula in Physics
The formula for calculating the stress applied to a body is as follows-
Stress = (Restoring Force) / (Area of Material)
As a result, we utilize notation to represent stress.
Stress in Physics: Hooke’s law
Hooke's law states thatwhen a material is loaded within its elastic limit, thestress created in the body is directly proportionate to the strain produced. Thus, within the elastic limit, the stress-strain ratio is constant. The modulus of elasticity, modulus of rigidity, or elastic moduli is the name given to this constant.
Applications of Stress in Physics in Real Life
Every day, professions like mechanical engineering and architecture use the idea of stress. Here are a few general instances of how stress is used-
- In architecture, the idea of stress is utilized to develop a building's structural layout.
- Mechanical engineering and industries like robotics also make extensive use of stress.
- The notion of stress and how it impacts the various sections of the building is included in every aspect of the structure, including the building's foundation, support beams, and columns.
- To avoid any accidents, it is essential to understand how various mechanical components could put stress on one another.
Points to Remember
- Normal stress and Shearing stress are the two main forms of stress.
- Longitudinal Stress and Bulk Stress are the two categories of normal stress.
- The external restorative force applied per unit area of a body is described as stress.
- The magnitude of forces that create deformation in an item is described by stress.
- The Stress Formula is stated as = F / A, where F is the applied force and A is the area on which the force acts.
- The stress symbol is and it is a scalar quantity.
Sample Questions of Stress in Physics
Sample Question 1: In the event of shearing stress, what is the direction of the deforming force?
Solution: The deforming force in shearing stress is parallel to the cross-sectional area.
Sample Question 2: What is the stress unit?
Solution: N/m2 or Pascal is the SI unit of stress.
Sample Question 3: Define long-term stress.
Solution: Longitudinal stress is the stress that an item experiences throughout its length when equal and opposing deforming forces perpendicular to the area of the cross-section are present.
Sample Question 4: What impact does tangential stress have on an object?
Solution: Tangential tension causes the form of an item to shift.
Sample Question 5: A coil spring's stretching is determined by its shear modulus. How?
Solution: When a coil spring is stretched, neither its length nor volume change; only its shape does. As a result, coil spring stretching is determined by shear modulus.
