Grade 9
  1. Mechanics  1.1. Motion  1.1.1. Types of motion  1.1.2. Distance and displacement  1.1.3. Speed and Velocity  1.1.4. Acceleration  1.1.5. Graphical representation of motion  1.1.6. Equations of motion  1.1.7. Uniform and non-uniform motion  1.1.8. Free fall and acceleration due to gravity  1.1.9. Relative speed  1.1.10. Circular motion  1.2. Laws of force and motion  1.2.1. The concept of force  1.2.2. newton's first law of motion  1.2.3. Newton's second law of motion  1.2.4. Newton's third law of motion  1.2.5. Inertia and types of inertia  1.2.6. Motion  1.2.7. Conservation of momentum  1.2.8. Application of Newton's laws in daily life  1.2.9. Types of Forces (Contact and Non-Contact)  1.2.10. Friction and its effects  1.3. Gravitational force  1.3.1. Newton's law of universal gravitation  1.3.2. Importance of Gravitational Force  1.3.3. Acceleration due to gravity  1.3.4. Free fall and weightlessness  1.3.5. Mass and weight  1.3.6. Variation of g with height and depth  1.3.7. Kepler's laws of planetary motion  1.3.8. Satellites and their orbits  1.4. Work, Energy and Power  1.4.1. Concept of work  1.4.2. Positive and negative actions  1.4.3. Work done by constant and variable force  1.4.4. Energy and its forms  1.4.5. Kinetic energy and potential energy  1.4.6. Law of conservation of energy  1.4.8. Commercial unit of energy  1.4.9. Work–energy theorem  1.5. Simple machines  1.5.1. Types of simple machines  1.5.2. Mechanical advantage  1.5.3. Machine efficiency  1.5.4. Levers and their types  1.5.5. Pulleys and Inclined Planes  1.5.6. Gears and their uses
  2. Properties of matter  2.1. States of matter  2.1.1. Solids, liquids and gases  2.1.2. Properties of different states of matter  2.1.3. Change in state of matter  2.1.4. Plasma and Bose–Einstein condensate  2.2. Density and pressure  2.2.1. Concept of density and relative density  2.2.2. Pressure in solids, liquids and gases  2.2.3. Pascal's law and its applications  2.2.4. Atmospheric pressure and its variations  2.2.5. Surface tension and capillarity  2.3. Buoyancy and Archimedes' principle  2.3.1. Buoyant force  2.3.2. Archimedes principle  2.3.3. Applications of Archimedes' Principle  2.3.4. floating and sinking objects  2.3.5. Theory of Flotation and Archimedes' Principle
  3. Heat and Thermodynamics  3.1. Temperature and heat  3.1.1. Concept of heat and temperature  3.1.2. Temperature measurement  3.1.3. Temperature scales  3.2. Heat transfer  3.2.1. Conduction of heat  3.2.2. Convection of heat  3.2.3. heat radiation  3.2.4. Applications of heat transfer  3.2.5. Thermal conductivity  3.3. Thermal expansion  3.3.1. Expansion of solids, liquids and gases  3.3.2. Abnormal expansion of water  3.3.3. Applications of Thermal Expansion  3.4. Specific heat capacity and latent heat  3.4.1. Concept of specific heat capacity  3.4.2. Measurement and applications of specific heat  3.4.3. Latent heat of fusion and vaporization  3.4.4. Heat Engines and Efficiency
  4. Waves and sound  4.1. Waves and their types  4.1.1. Mechanical and electromagnetic waves  4.1.2. Longitudinal and Transverse Waves  4.1.3. Properties of Waves  4.1.4. Wavelength, frequency and speed of the wave  4.1.5. Superimposition of waves  4.2. Sound waves  4.2.1. Nature and transmission of sound  4.2.2. Speed of sound in different mediums  4.2.3. Reflection of sound and echo  4.2.4. Sonar and ultrasound  4.2.5. Resonance and pulsation  4.3. Sound characteristics  4.3.1. Intensity, loudness and quality of sound  4.3.2. Doppler effect in sound
  5. Lighting and Optics  5.1. Reflection of light  5.1.1. Laws of reflection  5.1.2. Reflection from a plane mirror  5.1.3. Reflection from a spherical mirror  5.1.4. Image formation by concave and convex mirrors  5.1.5. Applications of Reflection  5.2. Refraction of light  5.2.1. Laws of refraction  5.2.2. Refractive index  5.2.3. Refraction through a glass slab  5.2.4. Refraction in water and air  5.2.5. Lenses and their types  5.2.6. Image formation by convex and concave lenses  5.2.7. Total internal reflection and its applications  5.3. Dispersion and scattering of light  5.3.1. Spectrum of white light  5.3.2. Prisms and Dispersion  5.3.3. Tyndall effect and blue sky
  6. Electricity and Magnetism  6.1. Electric charge and static electricity  6.1.1. The concept of electric charge  6.1.2. Charging by friction, contact and induction  6.1.3. Electroscope and its working  6.2. Current Electricity  6.2.1. The concept of electric current  6.2.2. Ohm's Law and Resistance  6.2.3. Factors affecting resistance  6.2.4. Series and Parallel Circuits  6.2.5. Heating effect of electric current  6.2.6. Electric power and energy  6.3. Magnetism  6.3.1. Natural and artificial magnets  6.3.2. Properties of magnets  6.3.3. Earth's magnetism  6.3.4. Magnetic field and field lines  6.3.5. Electromagnets and their applications
  7. Modern Physics  7.1. structure of the atom  7.1.1. Atomic Structure and Subatomic Particles  7.1.2. Electrons, Protons, and Neutrons  7.1.3. Rutherford and Bohr model  7.2. Radioactivity  7.2.1. Types of radioactive emissions  7.2.2. Half-life and radioactive decay  7.2.3. Uses and Hazards of Radioactivity
  8. Space science and astronomy  8.1. The universe and its components  8.1.1. Stars and galaxies  8.1.2. Planets and Solar System  8.2. Satellites  8.2.1. Natural and artificial satellites  8.2.2. Use of satellites

Grade 9 → Mechanics → Laws of force and motion ↓


Application of Newton's laws in daily life


Isaac Newton's laws of motion lay the foundation for understanding the principles of force and motion. Newton's laws explain the relationship between an object and the forces acting on it and provide a framework for analyzing the motion of objects in our everyday lives. Newton's laws of motion are divided into three main principles: the first law (inertia), the second law (acceleration), and the third law (action and reaction). Let's explore each of these laws and see how they manifest in our daily experiences.

Newton's first law of motion: Law of inertia

Newton's first law, often called the law of inertia, states:

An object at rest remains at rest, and an object in motion continues to move with the same speed and in the same direction unless an unbalanced force acts on it.

This means that objects will not change their state of motion unless a force is applied. This is why a ball does not start rolling on the floor by itself, or why a car continues moving on the highway even when its engine is turned off, being subject only to forces such as air resistance and friction.

Example 1: A book on the table

A book kept on a table remains at rest unless someone applies a force to move it. The book remains at rest due to its inertia.

Booktable

Example 2: Moving car

Imagine a car moving at a constant speed on a straight road. It continues moving at the same speed and in a straight line as long as the force from the engine is balanced by the force of friction and air resistance.

car

Effect of unbalanced forces

When unbalanced forces act on an object, they change its state of motion. For example, pressing the brake pedal applies an unbalanced force to a car, causing it to stop.

Newton's second law of motion: F = ma

The second law of motion describes how the velocity of an object changes when an external force is applied to it:

The acceleration of an object is proportional to the net force acting on it and inversely proportional to its mass.
F = ma

Here, F is the applied force, m is the mass of the object, and a is the acceleration.

Example 3: Pushing a shopping cart

When you apply force to a shopping cart, it accelerates in the direction of the applied force. A heavier cart (more mass) requires more force to achieve the same acceleration as a lighter cart.

Force

Example 4: Sports activities

In sports, athletes take advantage of this law to improve their performance. For example, in the shot put, athletes apply maximum force to the shot, causing the shot to accelerate and travel maximum distance. The heavier the shot (more mass), the more force is needed to achieve greater acceleration.

Example 5: Driving a car

When you press the accelerator pedal during daily driving, the car's engine generates force and increases the speed of the car. More force is required to increase the speed of a heavy vehicle.

Newton's third law of motion: Action and reaction

The third law of motion states:

Every action has an equal and opposite reaction.

This means that forces always occur in pairs. If one object exerts a force on another object, the second object exerts an equal and opposite force on the first object.

Example 6: Walking

When you walk, your foot pushes the ground back (action), and the ground pushes your foot forward with an equal force (reaction). This reaction propels you forward, allowing you to walk.

Example 7: Swimming

Swimming offers a clear example of Newton's third law. When swimmers push water backward with their arms, the water pushes them forward, helping them move forward through the water.

actionfeedback

Example 8: Launching a rocket

When the rocket engine throws gas downward at high speed (action), the rocket is pushed upward by an equal and opposite force (reaction). This is the principle that allows rockets to be launched into space.

Understanding real-life applications

By examining these laws and their applications, we can better understand the mechanics of everyday activities and events.

Handling objects

Our daily activities involve handling various objects, where Newton's laws come into play. Whether lifting, pushing or pulling objects, the forces involved can be analysed using these laws.

Engineering and security

Engineers apply Newton's laws in designing safer structures and transportation systems. For example, car manufacturers use these principles in crash testing to understand the effects of forces on car safety features such as airbags and seatbelts.

Conclusion

Newton's laws of motion are fundamental to understanding how forces affect the motion of objects. These laws apply in a variety of real-life situations, providing a scientific basis for the motion and interactions of objects. By understanding and applying these principles, we can better explain everyday phenomena and make informed decisions in technological and scientific fields.


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Application of Newton's laws in daily life

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