Grade 10
  1. Mechanics  1.1. Dynamics  1.1.1. Motion in one dimension  1.1.2. Motion in two dimensions  1.1.3. Displacement and Distance  1.1.4. Speed and Velocity  1.1.5. Acceleration  1.1.6. Graphical representation of motion  1.1.7. Equations of motion  1.1.8. Free fall and acceleration due to gravity  1.1.9. Projectile motion  1.1.10. Relative speed  1.2. Dynamics  1.2.1. Newton's Laws of Motion  1.2.2. Inertia and mass  1.2.3. Force and its types  1.2.4. action and reaction force  1.2.5. Friction and its effects  1.2.6. Coefficient of friction  1.2.7. Circular motion  1.2.8. Centripetal force and centripetal acceleration  1.2.9. Momentum and Impulse  1.2.10. Conservation of momentum  1.2.11. Newton's third law and applications  1.3. Work, Energy and Power  1.3.1. Work done by the force  1.3.2. Work–energy theorem  1.3.3. Kinetic energy  1.3.4. Potential energy  1.3.5. Mechanical energy  1.3.6. Energy Conservation  1.3.7. Power and efficiency  1.3.8. Renewable and non-renewable energy sources  1.4. Gravitational force  1.4.1. Newton's law of universal gravitation  1.4.2. Gravitational field and field strength  1.4.3. Acceleration due to gravity on different planets  1.4.4. Kepler's laws of planetary motion  1.4.5. Orbits and satellites  1.4.6. Weight and apparent weight  1.4.7. Gravitational potential energy
  2. Properties of matter  2.1. States of matter  2.1.1. Solid, liquid and gas  2.1.2. Molecular structure of matter  2.1.3. Intermolecular forces  2.1.4. Plasma and Bose–Einstein condensate  2.2. Pressure  2.2.1. Definition of Pressure  2.2.2. Pressure in liquids  2.2.3. Atmospheric pressure  2.2.4. Pascal's principle  2.2.5. Archimedes' Principle and Buoyancy  2.2.6. Surface tension and capillarity  2.3. Elasticity  2.3.1. Hooke's law  2.3.2. Stress and strain  2.3.3. Elastic Limit and Modulus of Elasticity  2.3.4. Applications of Elasticity
  3. Thermal physics  3.1. heat and temperature  3.1.1. Difference Between Heat and Temperature  3.1.2. Temperature scale  3.1.3. Thermal expansion  3.1.4. Thermal equilibrium  3.2. Heat transfer  3.2.1. Conductivity  3.2.2. Convection  3.2.3. Radiation  3.2.4. Insulation and its applications  3.3. Thermal properties of matter  3.3.1. Specific heat capacity  3.3.2. Latent heat and phase change  3.3.3. Boiling and Melting Point  3.3.4. Heat engines and refrigeration  3.4. Laws of Thermodynamics  3.4.1. Zeroth law of thermodynamics  3.4.2. First law of thermodynamics  3.4.3. Second law of thermodynamics  3.4.4. Carnot cycle
  4. Waves and optics  4.1. Nature and properties of waves  4.1.1. Types of waves in nature and properties of waves  4.1.2. Transverse and longitudinal waves  4.1.3. Wave parameters  4.1.4. Reflection and refraction of waves  4.1.5. Superposition and Interference  4.1.6. Standing Waves and Resonance  4.1.7. Doppler effect  4.2. Sound waves  4.2.1. Characteristics of sound waves  4.2.2. Speed of sound in different mediums  4.2.3. Applications of sound waves  4.2.4. Ultrasound and its uses  4.3. Light Waves and Optics  4.3.1. Nature of light  4.3.2. Reflection of light  4.3.3. Laws of reflection  4.3.4. Mirrors and Image Formation  4.3.5. Refraction of light  4.3.6. Snell's Law  4.3.7. Lenses and Image Formation  4.3.8. Total internal reflection and critical angle  4.3.9. Optical fibre  4.4. Optical Instruments  4.4.1. Microscope  4.4.2. Telescope  4.4.3. Human eye and vision defects  4.4.4. Camera and its working principle
  5. Electricity and Magnetism  5.1. Electrostatics  5.1.1. Electric charge and its properties  5.1.2. Conductors and Insulators  5.1.3. Coulomb's law  5.1.4. Electric field and field lines  5.1.5. Electric potential and potential difference  5.1.6. Capacitors and Capacitance  5.2. Current Electricity  5.2.1. Electric current and its measurement  5.2.2. Ohm's law  5.2.3. Resistance and resistivity  5.2.4. Series and Parallel Circuits  5.2.5. Electric power and energy  5.2.6. Kirchhoff's Laws  5.3. Magnetism and Electromagnetism  5.3.1. Magnetic field and field lines  5.3.2. Magnetic effects of electric current  5.3.3. Electromagnetic induction  5.3.4. Faraday's laws of electromagnetic induction  5.3.5. Transformers and Applications  5.3.6. AC and DC current
  6. Modern Physics  6.1. Nuclear physics  6.1.1. Structure of the atom  6.1.2. Bohr's atomic model  6.1.3. Electron Energy Levels  6.1.4. X-rays and applications  6.2. Radioactivity  6.2.1. Types of radiation  6.2.2. Half-life and radioactive decay  6.2.3. Nuclear reactions and applications  6.2.4. Fission and Fusion  6.3. Quantum physics  6.3.1. Wave–particle duality  6.3.2. Photoelectric effect  6.3.3. Energy quantization  6.3.4. Heisenberg's uncertainty principle
  7. Electronics and Communication  7.1. Semiconductors  7.1.1. Conductors, Insulators and Semiconductors  7.1.2. Diodes and their applications  7.1.3. Transistors and Logic Gates  7.1.4. LEDs and photodiodes  7.2. Communication Systems  7.2.1. Basics of communication  7.2.2. Analog and digital signals  7.2.3. Wireless and optical fibre communication  7.2.4. Radio Waves and Modulation

Grade 10 → Mechanics → Dynamics ↓


Displacement and Distance


In dynamics, the concepts of displacement and distance are fundamental to understanding motion. These terms describe how much movement has occurred, but they are not the same thing. Let's explore their meaning, differences, and applications with simple examples and visual aids.

What is the distance?

Distance is a scalar quantity that tells “how far an object has covered during its motion”. It deals only with the magnitude of the path taken by the object, without considering the direction. This means that distance is always positive and it measures the entire path covered by an object, whether the path is straight or curved.

Distance example

Imagine you are running around a track oval. You start at a point called A and complete one lap around the track and return to A. If the circumference of the track is 400 m, the distance you have travelled is 400 m. Even if you do not return to your starting point, any path you take contributes to the total distance.

Distance = Total path covered by the object

What is displacement?

Displacement is a vector quantity that tells "how far an object is from its initial position". It takes into account both magnitude and direction. Displacement is the shortest direct path between the initial point and final point of an object. It can be positive, negative, or zero depending on the direction of the final position relative to the initial position.

Displacement example

Let's consider another scenario where you start from your home and walk to a nearby store which is 300 m north. Here the displacement will be 300 m in the north direction. If you walk back towards your home, your displacement will become 0 because you are back at the starting point even though you have walked 600 m (300 m to the store and 300 m back).

Displacement = Final position – Initial position

Comparing distance and displacement

To clearly explain the difference between distance and displacement, we can consider some more detailed examples:

Example 1: Walking in a straight line

Suppose you walk 5 m east and then turn and walk 3 m west. In this case:

  • Distance = 5 m + 3 m = 8 m
  • Displacement = 5 m east - 3 m west = 2 m east

Example 2: Traveling on a square path

Imagine you are walking the perimeter of a square park. Each side of the square is 50 meters long, and you start at one corner:

  • After completing the square (200m):
  • Distance = 50 + 50 + 50 + 50 = 200 meters
  • Displacement = 0, because you are back at the starting point

Example 3: A zig-zag path

If a person walks 3 m north, then 4 m east, the path is a right-angled triangle. Using the Pythagorean theorem, the displacement (hypotenuse) can be calculated as:

Displacement = √(3 2 + 4 2 ) = √(9 + 16) = √25 = 5 m

Visual example

Start Ending Distance = 260m

Figure: Visual representation of a straight line path with starting point, ending point, and distance.

Start Ending Displacement = 200 m

Figure: A curved path between two points with distance shown as a solid line and displacement shown as a dashed line.

Key points to remember

  • Distance is always a positive scalar quantity.
  • Displacement can be positive, negative, or zero, and it is a vector quantity.
  • The distance on a straight path without change of direction is equal to the displacement.
  • In looping paths the displacement can be zero while the distance cannot.
  • They have different applications depending on the circumstances where direction matters.

Applications of distance and displacement

In physics and real-world scenarios, both distance and displacement are used to describe and analyze motion. Here are some applications:

Navigational uses

Navigators use displacement to mark the exact position and direction from one point to another, often applied in maps and GPS systems.

Engineering and construction

Knowing the displacement helps determine the shortest path, which is important in construction projects, where a direct path can save costs and time.

Sports analysis

Sports coaches and analysts monitor players' movements on the field, where distances covered are important, but precise displacements provide information about strategic movements.

Conclusion

It is important to understand the concepts of distance and displacement, especially in physics, sports, navigation, and many other fields. While both measure aspects of motion, their applications and interpretations are very different. Distance measures 'how much' while displacement tells 'how far and in what direction'. Remember the applications and differences to effectively apply these concepts in real-world problems and scenarios.


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Displacement and Distance

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