IGCSE PHYSICS NOTES ON GENERAL PHYSICS
by Ayoub S
1. General Physics
1.1 Length and Time
- Length:
- Use a ruler for distances between 1mm and 1 meter.
- Smaller lengths: micrometer screw gauge.
- SI unit: meter (m).
- Volume of regular object: mathematical formula.
- Volume of irregular object: measuring cylinder with water displacement.
- Time:
- Measured using clocks or stopwatch.
- SI unit: second(s).
- Pendulum spin time: time ~25 circles, divide by the same number of circles.
1.2 Motion
- Speed:
- Distance moved per time unit.
- Measured in meters/second (m/s) or kilometers/hour (km/h).
- Speed = Total Distance / Total Time.
- Velocity:
- Speed in a specified direction (a vector).
- Speed Time Graphs:
- Area under the line = distance traveled.
- Gradient = Acceleration (m/s²).
- Positive acceleration = velocity increase.
- Negative acceleration (deceleration) = velocity decrease.
- Distance Time Graphs:
- Gradient = Speed (m/s).
- For constant speed: Speed × Time.
- For constant acceleration: Initial Speed + Final Speed / 2 × Time.
1.3 Mass and Weight
- Mass: Matter in a body, resistance to motion.
- Weight: Force of gravity on a body due to its mass.
- Weight = Mass × Gravity.
- Comparing weights: use a balance.
1.4 Density
- Density = Mass / Volume.
- Liquid Density: Measuring cylinder and balance.
- Solid Density: Volume (mathematical formula), mass (balance).
- Object floats if density < liquid; sinks if density > liquid.
1.5 Forces
- Measured in Newtons (N).
- Force = Mass × Acceleration.
- Resultant of forces, net force impact on motion.
IGCSE PHYSICS NOTES ON GENERAL PHYSICS
by Ayoub S
1.6 Moments
- Measure of turning effect on a body.
- Moment = Force × Perpendicular Distance.
- Equilibrium: Balanced moments mean no resultant force.
1.7 Centre of Mass
- Imaginary point in a body where total mass seems to act.
- Object stable when force by weight is within its base.
1.8 Scalars and Vectors
- Scalar: Only magnitude (e.g., speed).
- Vector: Magnitude and direction (e.g., velocity).
1.9 Momentum
- Product of mass and velocity.
- Conservation of linear momentum in an isolated system.
1.10 Energy
- Kinetic, gravitational, chemical, strain, nuclear, internal, electrical, light, sound.
- Conservation of energy; energy can be stored.
- Efficiency: Useful energy output / Energy input × 100%.
1.11 Energy Resources
- Renewable vs. Non-renewable sources, advantages, disadvantages.
1.12 Work and Power
- Work: Force × Distance.
- Power: Rate of work done.
1.13 Pressure
- Force per unit area, measured in Pascals (Pa).
- Pressure in liquids; increases with depth.
- Measuring pressure: Manometer, Barometer.
[End of Notes]