Course Content
Class 11 Physics Chapter 1 Physical World
Section Name Topic Name 1 Physical World 1.1 What is physics? 1.2 Scope and excitement of physics 1.3 Physics, technology and society 1.4 Fundamental forces in nature 1.5 Nature of physical laws
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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
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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
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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
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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
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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
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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
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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
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Law of Motion Class 11 Physics Notes and Solution

Law of Motion Class 11 Physics Notes and Solution

fs =< μs

mv2/r  =< μsN   

v2  =< μsNR/m = μsmgR/m = μsRg

v  =<  √ μsRg

This is the maximum speed of a car in circular motion on a level road.

Law of Motion Class 11 Physics Notes and Solution

In the vertical direction (Y axis)

Ncosϴ = fsinϴ + mg ——————–(i)

In horizontal direction (X axis)

fcosϴ + Nsinϴ = mv2/r  —————-(ii)

Since we know that f      μsN   

For maximum velocity, f = μsN

(i)becomes:

       Ncosϴ = μsNsinϴ + mg

Or, Ncosϴ – μsNsinϴ = mg

Or, N = mg/(cosϴ- μssinϴ)

Put the above value of N in (ii)

μsNcosϴ + Nsinϴ = mv2/r 

μsmgcosϴ/(cosϴ- μssinϴ) + mgsinϴ/(cosϴ- μssinϴ) = mv2/r 

mg (sinϴ + μscosϴ)/ (cosϴ – μssinϴ) = mv2/r 

Divide the Numerator & Denominator by cosϴ, we get

v2 = Rg (tanϴ +μs) /(1- μtanϴ)

v = √ Rg (tanϴ +μs) /(1- μtanϴ)

This is the miximum speed of a car on a banked road.

Special case:

When the velocity of the car = v,

  • No f is needed to provide the centripetal force. (μ=0)
  • Little wear & tear of tyres take place.

             vo = √ Rg (tanϴ)

 Problem: A circular racetrack of radius 300 m is banked at an angle of 15°. If the coefficient of friction between the wheels of a race-car and the road is 0.2, what is the

 (a) optimum speed of the racecar to avoid wear and tear on its tyres, and

(b) maximum permissible speed to avoid slipping ?

 Solution.

R = 300m

ϴ = 15o

μs  = 0.2

  • vo = √ Rg tanϴ

      = √300 * 9.8 * tan 15o

      = 28.1 m/s

  • vmax = √ Rg (tanϴ +μs) /(1- μtanϴ)

             = √ 300 * 9.8 * (0.2 + tan 15o)/(1-0.2tan15o)

             = 38.1 m/s

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