Course Content
Class 11 Physics Chapter 4 Motion In A Plane
4 Motion in a plane 4.1 Introduction 4.2 Scalars and vectors 4.3 Multiplication of vectors by real numbers 4.4 Addition and subtraction of vectors – graphical method 4.5 Resolution of vectors 4.6 Vector addition – analytical method 4.7 Motion in a plane 4.8 Motion in a plane with constant acceleration 4.9 Relative velocity in two dimensions 4.10 Projectile motion 4.11 Uniform circular motion
Class 11 Physics Chapter 5 Laws of motion
Section Name Topic Name 5 Laws of motion 5.1 Introduction 5.2 Aristotle’s fallacy 5.3 The law of inertia 5.4 Newton’s first law of motion 5.5 Newton’s second law of motion 5.6 Newton’s third law of motion 5.7 Conservation of momentum 5.8 Equilibrium of a particle 5.9 Common forces in mechanics 5.10 Circular motion 5.11 Solving problems in mechanics
Class 11 Physics Chapter 6 Work Energy and Power
Section Name Topic Name 6 Work Energy and power 6.1 Introduction 6.2 Notions of work and kinetic energy : The work-energy theorem 6.3 Work 6.4 Kinetic energy 6.5 Work done by a variable force 6.6 The work-energy theorem for a variable force 6.7 The concept of potential energy 6.8 The conservation of mechanical energy 6.9 The potential energy of a spring 6.10 Various forms of energy : the law of conservation of energy 6.11 Power 6.12 Collisions
Class 11 Physics Chapter 7 Rotation motion
Topics Introduction Centre of mass Motion of COM Linear Momentum of System of Particles Vector Product Angular velocity Torque & Angular Momentum Conservation of Angular Momentum Equilibrium of Rigid Body Centre of Gravity Moment of Inertia Theorem of perpendicular axis Theorem of parallel axis Moment of Inertia of Objects Kinematics of Rotational Motion about a Fixed Axis Dynamics of Rotational Motion about a Fixed Axis Angular Momentum In Case of Rotation about a Fixed Axis Rolling motion
Class 11 Physics Chapter 9 mechanics properties of solid
Section Name Topic Name 9 Mechanical Properties Of Solids 9.1 Introduction 9.2 Elastic behaviour of solids 9.3 Stress and strain 9.4 Hooke’s law 9.5 Stress-strain curve 9.6 Elastic moduli 9.7 Applications of elastic behaviour of materials
Class 11 Physics Chapter 11 Thermal Properties of matter
Section Name Topic Name 11 Thermal Properties of matter 11.1 Introduction 11.2 Temperature and heat 11.3 Measurement of temperature 11.4 Ideal-gas equation and absolute temperature 11.5 Thermal expansion 11.6 Specific heat capacity 11.7 Calorimetry 11.8 Change of state 11.9 Heat transfer 11.10 Newton’s law of cooling
Class 11 Physics Chapter 14 Oscillations
Section Name Topic Name 14 Oscillations 14.1 Introduction 14.2 Periodic and oscilatory motions 14.3 Simple harmonic motion 14.4 Simple harmonic motion and uniform circular motion 14.5 Velocity and acceleration in simple harmonic motion 14.6 Force law for simple harmonic motion 14.7 Energy in simple harmonic motion 14.8 Some systems executing Simple Harmonic Motion 14.9 Damped simple harmonic motion 14.10 Forced oscillations and resonance
Class 11th Physics Online Class For 100% Result
About Lesson


  • Strain is a measure of deformation representing the displacement between particles in the body to a reference length. 
  • It tells us how and what changes takes place when a body is subjected to strain. 
  • Mathematically:-  Strain = ΔL/L , where ΔL=change in length L= original length
  • It is dimensionless quantity because it is a ratio of two quantities. 
  • For example: – If we have a metal beam and we apply force from both sides the shape of the metal beam will get deformed. 
  • This change in length or the deformation is known as Strain.
Class 11 Physics Mechanical Properties of Solids Notes

Types of Strain: Longitudinal Strain

  • Change in length to the original length of the body due to the longitudinal stress.
  • If we apply longitudinal stress to a body either the body elongates or it compresses this change along the length of the body. This change in length is measured by Longitudinal Strain.
  • Longitudinal Strain = ΔL/L
  • Mathematically
    • Consider a rod whose initial length is L after elongation length becomes L’.
    • So the change in length is ΔL= L’ – L
    • So Strain= ΔL/L
  • Strain occurs as a result of stress.
Class 11 Physics Mechanical Properties of Solids Notes

Shearing Strain

  • Shearing strain is the measure of the relative displacement of the opposite faces of the body as a result of shearing stress.
  • If we apply force parallel to the cross – sectional area because of which there was relative displacement between the opposite faces of the body.
  • Shearing strain measures to what extent the two opposite faces got displaced relative to each other.
  • Mathematically:-
    • Consider a cube whose initial length was L which is at some position and when it gets displaced by an angle θ.
    • Let the small relative displacement be x.
  • Shearing strain= x/L
  • In terms of tan θ,
  • Shearing strain = tan θ = x/L
  • tan θ  is equal to  θ  (as θ is very small)
  • Therefore, x/L = θ
Class 11 Physics Mechanical Properties of Solids Notes

Volume Strain

  • Volume strain is defined as ratio of change in volume to the original volume as a result of the hydraulic stress.
  • When the stress is applied by a fluid on a body there is change in the volume of body without changing the shape of the body. 
  • Volume strain = ΔV/V 
  • For example:-
  • Consider a ball initially at volume V.
Class 11 Physics Mechanical Properties of Solids Notes
mechanical properties of solids

Problem:- Four identical hollow cylindrical columns of mild steel support a big structure of mass 50,000 kg. The inner and outer radii of each column are 30 cm and compressional strain of each column.


Mass of the big structure, M = 50,000 kg 

Inner radius of the column, r = 30 cm = 0.3 m

Outer radius of the column, R = 60 cm = 0.6 m

Young’s modulus of steel, Y = 2 × 1011 Pa

Total force exerted, F = Mg = 50000 × 9.8 N

Stress = Force exerted on a single column = 122500 N

Young’s modulus, Y =𝑆𝑡𝑟𝑒𝑠𝑠/𝑆𝑡𝑟𝑎𝑖𝑛


Area, A = π (R2 – r2) = π ((0.6)2 – (0.3)2)

Strain = 122500/ (π [0.6)2 – (0.3)2] x 2×1011)

= 7.22 × 10–7

Hence, the compressional strain of each column is 7.22 × 10–7

Wisdom TechSavvy Academy