Paper 2

• This is good for AQA GCSE Physics Paper 2, Higher and Foundation Tier, Double Combined Trilogy, Triple, or Separate Physics
• Topics covered

  • Forces
  • Waves
  • Magnetism
  • Space (only for Triple)
• A force is any push or pull
• Types of forces

  • Contact forces (e.g., pushing a door)
  • Non-contact forces (e.g., magnetism, electrostatic forces, gravity)
• Normal contact force

  Electrostatic repulsion between electrons in your skin and the door
• Other contact forces


  • Friction
  • Air resistance
  • Tension
• Vectors

  Arrows that show the direction and magnitude of a force
• Finding resultant force at right angles

  Using Pythagoras theorem
• Forces are balanced when they add up to zero, leading to no acceleration (Newton's first law of motion)
• Scalar vs. Vector quantities

  Scalar has magnitude only, while vector has magnitude and direction
• Examples of scalar and vector quantities

  • Displacement (vector)
  • Velocity (vector)
  • Weight (scalar)
• Weight is the force due to gravity acting on an object, calculated by mass * gravitational field strength (9.8 N/kg on Earth)
• To lift an object at a constant speed, the lifting force must equal the weight of the object
• Calculating work done in lifting an object


  Using the equation: work done = force * distance moved
• Work done is a fancy term for energy transferred by a force
• The equation for work done is also used to calculate gravitational potential energy (GPE)
• Hook's Law


  Force equals spring constant times extension for elastic objects
• Spring constant unit is newton per meter
• Energy stored in a spring is proportional to the force applied
• Ensure to avoid systematic errors by aligning ruler zero mark with the bottom of the spring and avoiding parallax errors
• Length of the whole spring would introduce a systematic error if measured incorrectly
• Ensure you're at eye level with the bottom of the spring when measuring against the ruler to avoid Parallax error
• Parallax error is a random error rather than a systematic error
• Energy stored in the spring

  Equal to half k^ s
• If an object attached to the spring is let go, it would gain the same amount of kinetic energy in an ideal or closed system where no energy is lost to the surroundings
• Moment

  A turning force, for example, what you do with a spanner
• Moment equation

  Force times distance to the pivot, unit is newton meters
• Principle of Moments: If moments turning clockwise are balanced with moments turning anticlockwise, the object will not turn
• Application of moments is seen in Gears where a small gear can turn a large gear to increase the produced moment
• Pressure

  Force divided by area, unit is Newton per square meter or pascals (PA)
• Pressure increases with depth underwater due to the weight of the water above pushing down
• Pressure calculation: p = Hρg, where H is height, ρ is density, and g is gravitational field strength
• Gas pressure is due to collisions of gas particles with surfaces, can be increased by adding more gas, reducing volume, or raising temperature
• Altitude affects atmospheric density and pressure decreases at higher altitudes
• Speed and velocity are measured in m/s, with velocity having direction
• Speed and velocity are calculated by distance or displacement over time
• Acceleration is the change in speed over time, unit is m/s squared
• Negative acceleration indicates deceleration or slowing down
• Gravity accelerates objects downwards at a constant rate of 9.8 m/s squared
• Area under a velocity-time graph gives distance traveled