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 2 Unit and Measurements
Unit and Measurements
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Class 11 Physics Chapter 3 Motion In A Straight Line
Section Name Topic Name 3 Motion in a Straight Line 3.1 Introduction 3.2 Position, path length and displacement 3.3 Average velocity and average speed 3.4 Instantaneous velocity and speed 3.5 Acceleration 3.6 Kinematic equations for uniformly accelerated motion 3.7 Relative velocity
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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 8 Gravitation
Section Name Topic Name 8 Gravitation 8.1 Introduction 8.2 Kepler’s laws 8.3 Universal law of gravitation 8.4 The gravitational constant 8.5 Acceleration due to gravity of the earth 8.6 Acceleration due to gravity below and above the surface of earth 8.7 Gravitational potential energy 8.8 Escape speed 8.9 Earth satellite 8.10 Energy of an orbiting satellite 8.11 Geostationary and polar satellites 8.12 Weightlessness
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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 10 Mechanical Properties of Fluids
Section Name Topic Name 10 Mechanical Properties Of Fluids 10.1 Introduction 10.2 Pressure 10.3 Streamline flow 10.4 Bernoulli’s principle 10.5 Viscosity 10.6 Reynolds number 10.7 Surface tension
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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 12 Thermodynamics
Section Name Topic Name 12 Thermodynamics 12.1 Introduction 12.2 Thermal equilibrium 12.3 Zeroth law of thermodynamics 12.4 Heat, internal energy and work 12.5 First law of thermodynamics 12.6 Specific heat capacity 12.7 Thermodynamic state variables and equation of state 12.8 Thermodynamic processes 12.9 Heat engines 12.10 Refrigerators and heat pumps 12.11 Second law of thermodynamics 12.12 Reversible and irreversible processes 12.13 Carnot engine
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Class 11 Physics Chapter 13 Kinetic Theory
Section Name Topic Name 13 Kinetic Theory 13.1 Introduction 13.2 Molecular nature of matter 13.3 Behaviour of gases 13.4 Kinetic theory of an ideal gas 13.5 Law of equipartition of energy 13.6 Specific heat capacity 13.7 Mean free path
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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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Class 11 Physics Chapter 15 Waves
Section Name Topic Name 15 Waves 15.1 Introduction 15.2 Transverse and longitudinal waves 15.3 Displacement relation in a progressive wave 15.4 The speed of a travelling wave 15.5 The principle of superposition of waves 15.6 Reflection of waves 15.7 Beats 15.8 Doppler effect
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Class 11th Physics Online Class For 100% Result

Introduction ( Class 11 Physics Gravitation )

• Whenever we throw an object towards the sky it will fall back onto the ground.
• For Example: – A ball comes down when thrown up. Rain drops fall towards the ground; Planets revolve in an elliptical orbit around sunetc.

Planets revolving in the elliptical orbit.

Leaves fall off the tree.

• There is a force due to which all things are attracted towards the earth. This force is known as Gravitation.
• Gravitation is the force of attractionbetween all masses in the universe, especially the force of attraction exerted by the earth on all the bodies near its surface.
• In this chapter we will take a look at gravitation force, its laws, and we will also study about the planetary motion.

Gravitational Constant

Newton’s view of Gravitation

• Newtonwas the first scientist who studied the force of gravitation.
• According to him there is a force which is exerted by the surface of the earth because of which all the objects are attracted towards the surface of the earth.
• He also concluded that all objects in this universe attract each other with a force. This force is Gravitation force.
• F ∝ m1m2
• Force is ∝to the product of masses of 2 bodies.
• F ∝ 1/r2
• Force is inversely proportional to the square of the distance between the 2 bodies.
• Combining above equations:-
• F ∝ m1m2/r2
• F= G m1m2/r2

Where G = universal Gravitational constant.

• Its value is constant and it never changes.
• m1 and m2are masses of 2 bodies.
• r = distance between the bodies.

Gravitational Constant: Cavendish experiment

• Cavendish performed an experiment to calculate the value of G.
• To calculate the value of G he took a wooden plank and attached two 2 balls on either side of the plank and hung this with a thin thread from the top.
• He introduced 2 very big balls and those balls are near the smaller balls.
• He observed that the small balls got attracted to big balls and wooden plank started rotating and as a result the thin thread started twisting.
• This happened because of force of attraction between the small balls and bigger balls.
• He observed that :-
1. Plank rotates till twisting force becomes equal to the gravitational force between the balls.

𝛕 = G m1m2/r2

LƟ = G m1m2/r2

• By using the above equation he calculated the value of G,
• G= 6.67×10-11Nm2/kg2
• Units of G : Nm2/kg2

Problem:- Calculate the gravitational force of attraction between 2 lead balls of mass 20kg and 10kg separated by a distance of 10cm?

Answer: m1= 20kg , m2=10kg , r=10cm = 10/100 = 0.1m

G=6.67×10-11Nm2/kg2

F=G m1m2/r2

= 6.67×10-11x 20×10 / (0.1)2

F = 1.3 x 10-6N

Acceleration due to gravity of the earth

• Acceleration attained due to gravity of earth.
• All the objects fall towards the earth because of gravitational pull of the earth.
• And when abody is falling freely, it will have some velocity and therefore it will attain some acceleration. This acceleration is known as acceleration due to gravity.
• It is a vector quantity.
• Denoted by ‘g’.
• Its value is 9.8m/s2.

Example:-Stones falling from a rock will have some velocity because of which some acceleration. This acceleration is due to the force exerted by the earth on the rocks.This is known as acceleration due to gravity. 