Paper 2

• Scalar Quantities

  • Scalar quantities only have a magnitude.
  • E.g. Temperature, Mass, Energy
  • The sum of scalar quantities can be found by adding their values.
• Vector Quantities

  • Vector quantities only have both magnitude and an associated direction.
  • E.g. Force, Velocity, Displacement
  • The direction of a vector can be given in a written description, or drawn as an arrow.
• Contact Forces

  • Forces that act between two objects that are physically touching.
  • E.g. Tension, Friction, Air resistance.
• Non-Contact Forces

  • Forces that act between two objects that are not physically touching each other.
  • E.g. Magnetic force, Electrostatic force, Gravitational force.
• Weight, Mass and Gravity

  Weight = Mass × Gravitational field strength

  • Weight is measured in Newtons (N)
  • Mass is measured in Kilograms (kg)
  • Gravitational field strength is measured in newtons per kilogram (N/kg)
• Work Done

  Work is done when energy is transferred from one store to another.

  Work done = Force × Distance

  • Work Done is measured in Joules (J)
  • Force is measured in Newtons (N)
  • Distance is measured in Meters (M)
• Hookes Law

  Force = Spring Constant x Extension
• Newtons First Law

  • 'An object in motion stays in motion and a stationary object stays stationary unless acted on by another force.'
  • The tendency of an object to continue in its current state is called inertia.
• Newtons Second Law

  Resultant force = Mass × Acceleration

  • The acceleration of an object is proportional to the resultant force on the object and inversely proportional to the mass of the object.
• Newtons Third Law

   'Every action has an equal and opposite reaction'
• Waves

  • rest position - the undisturbed position of particles or fields when they are not vibrating
  • displacement - the distance that a certain point in the medium has moved from its rest position
  • peak - the highest point above the rest position
  • trough - the lowest point below the rest position
  • amplitude - the maximum displacement of a point of a wave from its rest position
  • wavelength - distance covered by a full cycle of the wave, usually measured from peak to peak, or trough to trough

  
• EM Spectrum

  All EM waves are emitted and absorbed by electrons.

  • Radio Waves = phones, Tv, wifi
  • Microwaves = cooking
  • Infrared = night vision
  • Visible Light = vision
  • Ultraviolet = tanning, can cause skin cancer
  • X-rays = medical scans
  • Gamma Rays = sterilisation