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 → Motion ↓


Uniform and non-uniform motion


Speed is a fundamental concept in physics that describes the movement of an object from one place to another with respect to time. In this detailed discussion, we will explore two types of speed: uniform speed and non-uniform speed. Both play an important role in understanding the motion of objects in our world, and they lay the foundation for more complex concepts in physics.

What is uniform motion?

Uniform motion refers to the movement of an object in a straight line at a constant speed. In uniform motion, the object covers equal distances in equal intervals of time. There is no change in the speed of the object during the period in which it is moving uniformly.

Imagine a car moving on a straight highway at a constant speed of 60 kilometers per hour. This car is an example of uniform motion because it covers the same distance every hour without any change in its speed.

Start Ending

In the above animation, the red dot represents an object moving uniformly from the start to the end point.

Mathematical representation of uniform motion

The formula for uniform motion can be simply expressed as follows:

Distance = Speed × Time

The implication of this formula is that if you know any two of the three quantities (distance, speed, time), then you can calculate the third quantity.

What is non-uniform motion?

Non-uniform motion occurs when an object travels unequal distances in equal intervals of time. In other words, the speed of the object is not constant, and it may accelerate (increase in speed) or decelerate (decrease in speed).

Consider an airplane taking off. It starts out slow, speeds up quickly, and then slows down again while it's in the air. This is an example of non-uniform motion.

Start Ending

In the animation, the blue dot represents an object experiencing uneven motion along a curved path, and its speed also changes as it moves.

Measuring uneven motion

Non-uniform motion is characterized by variable speed. To accurately describe the motion, we may need to calculate the average speed and instantaneous speed.

Average speed

Average speed is defined as the total distance traveled divided by the total time taken. The formula for average speed is:

Average Speed = Total Distance / Total Time

This provides a general idea of how fast an object is moving overall, but it does not take into account changes in speed at any given moment.

Instantaneous speed

Instantaneous speed shows how fast an object is at a particular moment. This is especially important for objects with uneven motion, as it allows us to understand the exact speed at any specific time.

Difference between uniform and non-uniform motion

  • In uniform motion the speed remains constant; in non-uniform motion the speed keeps changing.
  • Uniform motion results in equal distances being covered per unit of time; non-uniform motion results in unequal distances being covered.
  • In uniform motion the path is usually straight; in non-uniform motion the path may be curved or zigzag.

Real-world examples

Examples of uniform motion

  • A passenger train is running at a constant speed of 100 km/h on a level track without any change.
  • The minute hand of a watch moves uniformly as it moves around the dial.

Examples of non-uniform motion

  • A car accelerates through one stoplight and stops at another.
  • A roller coaster that rapidly descends one hill and slows down to climb another hill.

Conclusion

Understanding the difference between uniform and nonuniform motion is fundamental to understanding more complex physical phenomena. While uniform motion provides a simplified model of constant motion, nonuniform motion is more realistic, taking into account the variations we see in everyday life. By knowing these concepts, students can better understand the physics of how and why things move.


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Uniform and non-uniform motion

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