AQA GCSE Physics - Paper 1

• Energy


  Cannot be created or destroyed, only transferred usefully, stored or dissipated
• Kinetic energy


  The energy stored in moving objects
• Kinetic energy

  Measured in Joules (J)
• Mass

  Measured in kilograms (kg)
• Velocity


  Measured in metres per second (m/s)
• 1 kilojoule


  Equals 1000 joules
• Stretching a spring


  1. Force applied to change the length of the spring, doing work on the spring

  2. Stretched spring stores elastic potential energy
• Limit of proportionality exceeded


  Extension is no longer directly proportional to the force applied
• Inelastic deformation


  Spring will not return back to its original shape and may break
• Elastic potential energy

  Measured in Joules (J)
• Spring constant

  Measured in Newtons per metre (N/m)
• Extension

  Measured in metres (m)
• Gravitational potential energy


  Energy stored in an object due to its position above the Earth's surface due to the force of gravity acting on it
• Gravitational potential energy

  Measured in Joules (J)
• Height

  Measured in metres (m)
• Thermal energy


  Energy stored due to an object's temperature
• Specific heat capacity


  Amount of energy required to raise the temperature of 1kg of a substance by 1 degrees celsius
• System


  An object or a group of objects
• Closed system


  No energy can enter or leave
• Pendulum motion


  1. At top: maximum gravitational potential energy

  2. Swinging down: gravitational potential energy transferred to kinetic energy

  3. At bottom: maximum kinetic energy

  4. Swinging up: kinetic energy transferred to gravitational potential energy
• Friction


  Causes energy to be transferred to thermal energy (less useful energy is wasted)
• Reducing friction reduces unwanted energy transfers
• Bungee jump


  1. At start: all energy is gravitational potential energy

  2. Falling: gravitational potential energy transferred to kinetic energy

  3. Just as rope tightens: maximum kinetic energy

  4. Fully extended: no kinetic energy, maximum elastic potential energy

  5. Ascent: kinetic energy transferred back to gravitational potential energy

  6. At top: maximum gravitational potential energy

  7. Never returns to original position: energy dissipated as thermal energy due to friction and non-elastic stretching
• Work


  Energy transferred from one store to another
• Mechanical work


  Using a force to move an object
• Electrical work


  Current transferring energy
• Work done

  Measured in Joules (J)
• Force

  Measured in Newtons (N)
• Distance

  Measured in metres (m)
• Power


  Rate at which energy is transferred or rate at which work is done
• Power

  Measured in watts (W)
• Time

  Measured in seconds (s)
• Efficiency can be increased by reducing waste output and recycling waste output
• Thermal conductivity


  Rate of energy transfer by conduction across a material
• Reducing thermal conductivity of homes reduces thermal energy transfer
• Measuring specific heat capacity


  1. Measure mass, starting temperature, energy input, final temperature

  2. Specific heat capacity = change in thermal energy / (mass x temperature change)
• Specific heat capacity


  Measured in joules per kilogram degrees celsius (J/kg degrees celsius)
• Temperature change


  Measured in degrees celsius
• Sources of inaccuracy in specific heat capacity experiment: thermal energy loss, incomplete heating, thermometer error, uneven heating
• Comparing thermal insulation effectiveness

  1. Use beakers, hot water, thermometer, different insulating materials

  2. Independent variable: type of insulating material

  3. Dependent variable: temperature of water