physics paper 1

• Distance, Displacement, Speed and Velocity
• Quantities


  • Can be Vectors or Scalars
• Distance Travelled, Speed and Time


  Related by a formula
• Quantities and their values

  • Wing - 14 m/s (50 km/h)
  • Burning - 2 m/s (7 km/h)
  • Quad - 5.5 m/s (20 km/h)
  • Cace in a built-tree - 13 s (47 km/h)
  • Aeroplans - 250 m/s (900 km/h)
  • Cars on motorways - 33 m/s (120 km/h)
  • Isis - up to 55 m/s (200 km/h)
  • Wind speed - 5-20 m/s (18-72 km/h)
  • Speed of sound in air - 340 m/s (1224 km/h)
  • Eri - 15 m/s (54 km/h)
• When an object is stationary (not moving), its velocity (speed) is 0 m/s
• Measuring the speed of an object

  1. Using light gates

  2. Measuring the time taken to travel a certain distance
• It is important to understand this material for the rest of this topic
• More Uses of EM Waves

  • Photography using visible light
  • Games
  • Ultraviolet light used in fluorescent lamps
  • Infrared light used to heat water, used by some animals to detect prey
  • Microwaves used to produce images for security and sports
  • X-rays used to see inside things
  • Gamma rays used for sterilising and medical treatment
• Ultraviolet radiation


  Used in fluorescent lamps
• The atomic model has changed over time
• Plum pudding model


  Early model of the atom where electrons were thought to be embedded in a positive sphere
• Rutherford's model


  Proposed that the atom has a small, dense, positively charged nucleus surrounded by orbiting electrons
• Electrons can move between energy levels

  By absorbing or emitting electromagnetic radiation
• Isotopes


  Different forms of the same element
• Unstable isotopes


  Undergo radioactive decay
• Types of ionizing nuclear radiation

  • Alpha
  • Beta
  • Gamma
• Ionizing nuclear radiation


  • Has enough energy to remove electrons from atoms, causing them to become ions
  • Can damage living cells
• Mass and atomic number have to be balanced in nuclear equations
• Nuclear decay


  1. Radioactive nucleus emits radiation

  2. Nucleus changes to a more stable form
• Activity of a radioactive source

  The number of decays per second, measured in becquerels
• Half-life


  The time taken for the activity of a radioactive source to halve
• Radioactivity is a totally random process
• Calculating half-life


  1. Find the time when the activity has halved

  2. Divide the total time by the number of half-lives
• Irradiation


  Exposure to radiation
• Contamination


  Radioactive particles getting onto objects or people
• Ionizing radiation


  • Damages cells by ionisation
  • Can cause cell death or genetic damage
• Alpha and beta particles are the most dangerous types of radiation to be exposed to internally
• Quantition


  can be Vectors or Scalars
• Distance and Speed


  are Scalars, Displacement and Velocity are Vectors
• if the speed of an object is changing you can in the equation
• distance travelled (m)


  (average) speed (m) x time (s)
• To And the ineralend of an object, enge the feels to give


  (average) spead (m/s) distance travelled (m) +e(s)
• When an object is slafocery (not moving). He vesty (speed) in Day's
• for it to travel a certain distance and then using spend datase+ Fer
• (V-E)


  Change in velocity whe
• EXAMPLE


  • A statimay arise as it leads to a typical speed in 65
• Objects can have a Uniform Acceleration
• Finality


  Dial velocity (m)
• Acceleration In


  Distance (m)
• The Speed of a