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IGCSE Physics Unit 1 Revision Guide

Apr 27, 2025

IGCSE Physics Revision - Unit 1: General Physics and Mechanics

Introduction

  • This session covers IGCSE Physics Unit 1 revision for Cambridge and Edexcel syllabus.
  • The syllabus was updated in 2023:
    • Removed Topics: Barometer and manometer from pressure.
    • Added Topics: None to Unit 1.

Curriculum Overview

  • General Physics Topics: Measurements, Density, Speed and Acceleration, Introduction to Forces, Hooke’s Law, Newton's Laws of Motion, Momentum, Pressure, Moments, Energy (Work and Power), and Sources of Energy.

Key Concepts

1. Measurements

  • SI Units: Length (meters), Time (seconds), Mass (kilograms).
    • Others: Temperature (kelvin), Electric current (ampere).
  • Prefixes: Kilo (1000), Centi (0.01), Milli (0.001).
  • **Measuring Instruments: **
    • Length: Meter rule, measuring tape, micrometer.
    • Mass: Balance (top pan, spring balance, beam balance).
    • Techniques: Use multiple sheets to measure thickness, use blocks for spherical objects.

2. Density

  • Defined as mass/volume. Units: kg/m³ or g/cm³.
  • Effects on Density: Temperature changes, same material implies same density.

3. Speed and Acceleration

  • Speed: Distance over time; Velocity: Speed with direction.
  • Acceleration: Change in velocity over time; units: m/s².
  • Graphs: Distance-time and speed-time graphs used to analyze motion.

4. Forces

  • Types: Air resistance, friction, weight, upthrust, tension, normal contact force.
  • **Newton’s Laws of Motion: **
    • First Law: Object stays at rest/moving unless acted on by a force.
    • Second Law: F = ma (force equals mass times acceleration).
  • Resultant Force: Calculated by vector addition.

5. Hooke’s Law

  • Law: Extension is proportional to load (force) until elastic limit.
  • Formula: F = kx (force equals spring constant times extension).

6. Pressure

  • Definition: Force per unit area; units: Pascal (Pa).
  • In Liquids: Pressure = density × g × height (p = ρgh).
  • Total Pressure: Includes atmospheric pressure and liquid pressure.

7. Moments

  • Definition: Turning effect of a force; Moment = force × perpendicular distance.
  • Equilibrium: Clockwise moments equal anti-clockwise moments.

8. Energy

  • Types: Kinetic, Gravitational, Chemical, Elastic, Internal, Nuclear, Electrical.
  • Law of Conservation of Energy: Energy can be transformed but not created/destroyed.
  • Calculations:
    • Kinetic Energy: ½ mv²
    • Gravitational Potential Energy: mgh
    • Work: force × distance
    • Power: work/time
    • Efficiency: (useful energy output/total energy input) × 100

9. Sources of Energy

  • Renewable: Solar, wind, hydroelectric, wave, geothermal.
  • Non-renewable: Coal, oil, gas, nuclear.
  • Power Stations: Convert different forms of energy into electrical energy.

Important Notes

  • Read questions carefully for units and required conversions.
  • Extended sections include advanced calculations on energy and momentum.
  • Focus on understanding principles and applying them to solve problems.

This concludes the revision for Unit 1. Continue to practice past papers and familiarize yourself with both core and extended topics for comprehensive understanding.

Full transcript