Topics
Units and Measurements
- Quantitative Science
- System of Units
- Derived Quantities and Units
- Rules and Conventions for Writing SI Units and Their Symbols
- Measurement of Length
- Measurement of Mass
- Measurement of Time
- Dimensions and Dimensional Analysis
- Accuracy, Precision and Uncertainty in Measurement
- Errors in Measurements>Systematic Errors
- Errors in Measurements>Random Errors
- Estimation of Errors
- Combination of Errors
- Significant Figures
- Definitions of SI Units and Constants
Mathematical Methods
- Vector Analysis
- Scalar
- Vector
- Vector Operations>Multiplication of a Vector by a Scalar
- Vector Operations>Addition and Subtraction of Vectors
- Vector Operations>Triangle Law for Vector Addition
- Vector Operations>Law of parallelogram of vectors
- Resolution of Vectors
- Multiplication of Vectors
- Scalar Product(Dot Product)
- Vector Product (Cross Product)
- Concept of Calculus
- Differential Calculus
- Integral Calculus
Motion in a Plane
- Concept of Motion
- Rectilinear Motion
- Displacement
- Path Length
- Average Velocity
- Average Speed
- Instantaneous Velocity
- Instantaneous Speed
- Acceleration in Linear Motion
- Relative Velocity
- Motion in Two Dimensions-Motion in a Plane
- Average and Instantaneous Velocities
- Acceleration in a Plane
- Equations of Motion in a Plane with Constant Acceleration
- Relative Velocity in Two Dimensions
- Projectile Motion
- Uniform Circular Motion (UCM)
- Key Parameters of Circular Motion
- Centripetal Acceleration
- Conical Pendulum
Laws of Motion
- Fundamental Principles of Motion and Mechanics
- Types of Motion
- Aristotle’s Fallacy
- Newton’s Laws of Motion
- Newton's First Law of Motion
- Newton’s Second Law of Motion
- Newton's Third Law of Motion
- Inertial and Non-inertial Frames of Reference
- Types of Forces>Fundamental Forces in Nature
- Types of Forces>Contact and Non-Contact Forces
- Types of Forces>Real and Pseudo Forces
- Types of Forces>Conservative and Non-Conservative Forces
- Types of Forces>Work Done by a Variable Force
- Work Energy Theorem
- Principle of Conservation of Linear Momentum
- Collisions
- Elastic and Inelastic Collisions
- Perfectly Inelastic Collision
- Coefficient of Restitution e
- Expressions for Final Velocities in Elastic Head-On Collision
- Loss of Kinetic Energy in Perfectly Inelastic Head-On Collision
- Collision in Two Dimensions
- Impulse of a Force
- Necessity of Defining Impulse
- Rotational Analogue of a Force: Moment of a Force Or Torque
- Couple and Its Torque
- Proof of Independence of the Axis of Rotation
- Mechanical Equilibrium
- States of Equilibrium
- Centre of Mass>Mathematical Understanding of Centre of Mass
- Centre of Mass>Velocity of Centre of Mass
- Centre of Mass>Acceleration of Centre of Mass
- Centre of Mass>Characteristics of Centre of Mass
- Centre of Gravity
Gravitation
- Concept of Gravitation
- Kepler’s Laws
- Law of Orbit or Kepler's First Law
- Law of Areas or Kepler's Second Law
- Law of Periods or Kepler's Third Law
- Newton's Universal Law of Gravitation
- Measurement of the Gravitational Constant (G)
- Acceleration Due to Gravity (Earth’s Gravitational Acceleration)
- Variation in the Acceleration>Variation in Gravity with Altitude
- Variation in the Acceleration>Variation in Gravity with Depth
- Variation in the Acceleration>Variation in Gravity with Latitude and Rotation of the Earth
- Variation in the Acceleration>Effect of the shape of the Earth
- Gravitational Potential Energy
- Expression for Gravitational Potential Energy
- Connection of Potential Energy Formula with mgh
- Potential and Potential Difference
- Escape Velocity
- Earth Satellites
- Projection of Satellite
- Weightlessness in a Satellite
- Time Period of Satellite
- Binding Energy of an Orbiting Satellite
Mechanical Properties of Solids
- Mechanical Properties of Solids
- Elastic Behavior of Solids
- Stress and Strain
- Types of Stress and Corresponding Strain
- Hooke’s Law
- Elastic Modulus>Young’s Modulus
- Elastic Modulus>Bulk Modulus
- Elastic Modulus>Modulus of Rigidity
- Elastic Modulus>Poisson’s Ratio
- Stress-strain Curve
- Strain Energy
- Hardness of Material
- Friction in Solids
- Origin of Friction
- Types of Friction>Static Friction
- Types of Friction>Kinetic Friction
- Types of Friction>Rolling Friction
Thermal Properties of Matter
- Thermal Properties of Matter
- Temperature and Heat
- Measurement of Temperature
- Absolute Zero and Absolute Temperature
- Ideal Gas Equation
- Thermal Expansion
- Linear Expansion
- Areal Expansion
- Volume Expansion
- Relation Between Coefficient of Expansion
- Specific Heat Capacity
- Specific Heat Capacity of Solids and Liquids
- Specific Heat Capacity of Gas
- Heat Equation
- Thermal Capacity
- Calorimetry
- Change of State
- Analysis of Observation>From Point A to B
- Analysis of Observation>From Point B to D
- Temperature Effects and Considerations
- Evaporation vs Boiling
- Boiling Point and Pressure
- Factors Affecting Cooking
- Sublimation
- Phase Diagram
- Gas and Vapour
- Latent Heat
- Heat Transfer
- Conduction
- Thermal Conductivity
- Coefficient of Thermal Conductivity
- Thermal Resistance
- Applications of Thermal conductivity
- Convection
- Application of Convection
- Free and Forced Convection
- Radiation
- Newton’s Law of Cooling
Sound
- Sound Waves
- Common Properties of All Waves
- Transverse Waves
- Longitudinal Waves
- Mathematical Expression of a Wave
- The Speed of Travelling Waves
- The Speed of Transverse Waves
- The Speed of Longitudinal Waves
- Newton's Formula for Velocity of Sound
- Laplace’s Correction
- Factors Affecting Speed of Sound
- Principle of Superposition of Waves
- Echo
- Reverberation
- Acoustics
- Qualities of Sound
- Doppler Effect
- Source Moving and Listener Stationary
- Listener Approaching a Stationary Source with Velocity
- Both Source and Listener are Moving
- Common Properties between Doppler Effect of Sound and Light
- Major Differences between Doppler Effects of Sound and Light
Optics
- Fundamental Concepts of Light
- Nature of Light
- Ray Optics Or Geometrical Optics
- Cartesian Sign Convention
- Reflection>Reflection from a Plane Surface
- Reflection>Reflection from Curved Mirrors
- Total Internal Reflection
- Refraction of Light
- Applications of Total Internal Reflection
- Refraction at a Spherical Surface and Lenses
- Thin Lenses and Their Combination
- Refraction at a Single Spherical Surface
- Lens Makers' Equation
- Dispersion of Light
- Analysis of Prism
- Thin Prisms
- Some Natural Phenomena Due to Sunlight
- Defects of Lenses
- Optical Instruments
- Simple Microscope or a Reading Glass
- Compound Microscope
- Telescope
Electrostatics
- Concept of Electrostatics
- Electric Charge
- Basic Properties of Electric Charge
- Additive Nature of Charge
- Quantization of Charge
- Conservation of Charge
- Force between Charges
- Coulomb’s Law
- Scalar Form of Coulomb’s Law
- Relative Permittivity or Dielectric Constant
- Definition of Unit Charge from the Coulomb’s Law
- Coulomb's Law in Vector Form
- Principle of Superposition
- Electric Field
- Electric Field Intensity Due to a Point-Charge
- Practical Way of Calculating Electric Field
- Electric Lines of Force
- Electric Flux
- Gauss’s Law
- Electric Dipole
- Couple Acting on an Electric Dipole in a Uniform Electric Field
- Electric Intensity at a Point Due to an Electric Dipole
- Continuous Charge Distribution
Electric Current Through Conductors
- Concept of Electric Currents in Conductors
- Electric Current
- Flow of Current Through a Conductor
- Drift Speed
- Ohm's Law
- Limitations of Ohm’s Law
- Electrical Power
- Resistors
- Rheostat
- A combination of resistors in both series and parallel
- Specific Resistance
- Variation of Resistance with Temperature
- Electromotive Force (emf)
- Cells in Series
- Cells in Parallel
- Types of Cells
Magnetism
- Concept of Magnetism
- Magnetic Lines of Force
- The Bar Magnet
- Magnetic Field due to a Bar Magnet
- Magnetic Field Due to a Bar Magnet at an Arbitrary Point
- Gauss' Law of Magnetism
- The Earth’s Magnetism
Electromagnetic Waves and Communication System
- Foundations of Electromagnetic Theory
- EM Wave
- Sources of EM Waves
- Characteristics of EM Waves
- Electromagnetic Spectrum
- Radio Waves
- Microwaves
- Infrared waves
- Visible Light
- Ultraviolet rays
- X-rays
- Gamma Rays
- Propagation of EM Waves
- Ground (surface) Wave
- Space wave
- Sky wave propagation
- Communication System
- Elements of a Communication System
- Commonly Used Terms in Electronic Communication System
- Modulation
Semiconductors
- Concept of Semiconductors
- Electrical Conduction in Solids
- Band Theory of Solids
- Intrinsic Semiconductor
- Extrinsic Semiconductor
- n-type semiconductor
- p-type semiconductor
- Charge neutrality of extrinsic semiconductors
- p-n Junction
- A p-n Junction Diode
- Basics of Semiconductor Devices
- Applications of Semiconductors and P-n Junction Diode
- Thermistor
- Introduction
- Definition: Rolling Friction
- Characteristics
- Comparison of Friction Types
- Advantages of Friction
- Disadvantages of Friction
- Methods of Reducing Friction
- Real-Life Examples
Introduction
Friction is often called a "necessary evil" because it plays a dual role in our daily lives—helping us perform tasks like walking while also causing wear in machines. Rolling friction is a specific type of friction that occurs when an object rolls, offering much less resistance than sliding.
Definition: Rolling Friction
"Friction between two bodies in contact when one body is rolling over the other, is called rolling friction."
Characteristics
- Rolling Motion: Occurs when the point of contact of a body with a surface keeps changing continuously.
- Minimum Force: Rolling friction is the weakest form of friction compared to static or kinetic friction.
- Hierarchy of Friction:
Static Friction (Highest)
Kinetic Friction (Lower than static)
Rolling Friction (Lowest)
Comparison of Friction Types
The force of friction varies depending on the type of motion. For the same pair of surfaces, static friction is greater than kinetic friction. However, kinetic friction is still greater than rolling friction. Because rolling friction is the minimum, it is the most efficient way to move heavy objects.
Advantages of Friction
- Locomotion: Friction between the feet and the ground enables us to walk without slipping.
- Grip: Static friction allows us to hold objects firmly in our hands.
- Control: Vehicle brakes rely on friction to reduce speed or stop completely.
- Climbing: It provides the grip needed to climb trees or other surfaces.
Disadvantages of Friction
- Opposes Motion: It creates resistance against moving objects.
- Energy Loss: It produces heat and noise in various machine parts.
- Fuel Consumption: Engines in automobiles must burn more fuel to overcome friction.
Methods of Reducing Friction
To minimize the disadvantages, we use specific methods:
- Lubricants: Applying oil and grease to machine parts creates a smooth layer that reduces friction.
- Ball Bearings: These are used in machines to convert high kinetic friction into low rolling friction, increasing efficiency.
Real-Life Examples
- Ball Bearings: Used in bicycles and cars to ensure wheels turn smoothly by utilizing rolling friction.
- Tires: An inflated tyre rolls easily because it maintains its shape. A flat tyre deforms more, increasing the contact area and friction, making it harder to roll.
- Running on Sand: It is difficult to run fast on sand because the surface is loose and uneven, increasing the resistance (friction) against your feet compared to a hard road.


