IGCSE Physics: General Physics and Mechanics (Unit 1)

Updates to the 2023 Syllabus

• Removed Topics:
  • Pressure (barometer and manometer)
• New Topics:
  • None

Structure of Unit 1

1. Measurements and Density
2. Speed and Acceleration
3. Forces
4. Hooke's Law
5. Newton's Laws of Motion
6. Momentum (Extended)
7. Pressure
8. Moments
9. Energy, Work, and Power
10. Sources of Energy

Measurements and Density

• Key Quantities: Length, Time, Mass (SI units: meters, seconds, kilograms)
• Prefixes: Kilo (×1000), Centi (÷100), Milli (÷1000)
• Measuring Instruments:
  • Length: Meter rule, measuring tape, micrometer
  • Mass: Top-pan balance, spring balance, beam balance
  • Volume: Regular solids (length × width × height), liquids (measuring cylinder), irregular solids (water displacement)
• Density: Mass/Volume (kg/m³ or g/cm³)

Speed and Acceleration

• Speed: Distance/Time (m/s or km/h)
• Average Speed: Total Distance/Total Time
• Velocity: Speed with direction (vector)
• Acceleration: Change in velocity over time ( (\frac{\Delta v}{t}) or (\frac{v-u}{t}))
• Graphs:
  • Distance-Time Graph: Slope = Speed
  • Speed-Time Graph: Area under graph = Distance; Slope = Acceleration

Forces

• Types of Forces: Friction, Air Resistance, Weight, Upthrust, Tension, Normal Contact Force
• Friction: A resisting force that slows down motion; produces heat; can be reduced by lubrication
• Weight: Force of gravity on an object ((W = mg), g = 9.8 m/s²)
• Resultant Force: Sum of all forces acting on an object
• Drawing Forces: Use head-to-tail method or vector triangles to find resultant force

Hooke's Law

• Definition: Extension is proportional to load ((F = kx))
• Elastic Limit: Maximum force that a spring can handle without being permanently deformed

Newton's Laws of Motion

• First Law: An object at rest stays at rest, or in motion stays in motion, unless acted upon by a resultant force
• Second Law: (F = ma) (Force is the product of mass and acceleration)
• Third Law: For every action, there is an equal and opposite reaction

Momentum (Extended)

• Formula: Momentum = Mass × Velocity ((p = mv))
• Law of Conservation of Momentum: Total momentum before collision = Total momentum after collision

Pressure

• Definition: Force per unit area ((P = \frac{F}{A}))
• Pressure in Liquids: (P = \rho gh) (Depends on depth and density)
• Atmospheric Pressure: Sum of atmospheric pressure and liquid pressure

Moments

• Definition: Turning effect of a force (Moment = Force × Perpendicular Distance from Pivot)
• Equilibrium: Clockwise moments = Anti-clockwise moments
• Center of Mass: Point where the weight is considered to act
• Stability: Dependent on the width of the base and the height of the center of mass

Energy, Work, and Power

• Types of Energy: Kinetic, Gravitational Potential, Chemical, Elastic, Internal, Nuclear, Electrical
• Energy Transfer Methods: Waves, Heating, Doing Work, Electric Currents
• Calculations:
  • Kinetic Energy: (\frac{1}{2}mv²)
  • Gravitational Potential Energy: (mgh)
  • Work Done: Force × Distance ((W = Fd))
  • Power: Work/Time ((P = \frac{W}{t}))
  • Efficiency: (\frac{\text{Useful Energy Output}}{\text{Total Energy Input}} \times 100)

Sources of Energy

• Renewable: Solar, Wind, Hydro, Wave, Geothermal
  • Advantages: Renewable, low pollution
  • Disadvantages: Unreliable, less powerful
• Non-Renewable: Coal, Oil, Gas, Nuclear
  • Advantages: High energy output, reliable
  • Disadvantages: Pollution, non-renewable, nuclear waste
• Process of Energy Generation: Example Systems:
  • Fossil Fuels: Chemical → Heat → Mechanical → Electrical
  • Nuclear: Nuclear → Heat → Mechanical → Electrical
  • Hydroelectric: Gravitational Potential → Kinetic → Electrical
  • Wind: Kinetic → Electrical
  • Solar: Light → Electrical
  • Geothermal: Heat → Kinetic → Electrical

Remember to Review All Important Equations and Concepts!