Energy

• What is kinetic energy?

  Energy stored in moving objects
• Do stationary objects have kinetic energy?

  No, they have no kinetic energy
• What happens when we stretch a spring?

  We apply a force to change its length
• What is the relationship between force and extension in a spring?

  Force is directly proportional to extension
• What is elastic potential energy?

  Energy stored in a stretched spring
• What is gravitational potential energy?

  Energy stored due to an object's position
• What does specific heat capacity measure?

  Energy to raise 1kg by 1°C
• What is thermal energy?

  Energy stored due to an object's temperature
• What is the law of conservation of energy?

  • Energy can be transferred, stored, or dissipated
  • Energy cannot be created or destroyed
• What is a closed system?

  An object or group with no energy exchange
• What happens to gravitational potential energy (GPE) in a pendulum?

  GPE is transferred to kinetic energy
• What causes a pendulum to gradually stop swinging?

  Energy dissipated as thermal energy
• How can we reduce unwanted energy transfers in a pendulum?

  By reducing friction with lubricants
• What happens to energy during a bungee jump?

  GPE is transferred to kinetic energy
• What occurs when the bungee rope tightens?

  Kinetic energy is at its maximum
• Why does a bungee jumper not return to the original position?

  Energy is dissipated as thermal energy
• What is work done by a force?

  Energy transferred from one store to another
• What happens when a car brakes?

  Kinetic energy is transferred to thermal energy
• What is a watt?

  Energy transfer of 1J per second
• How can efficiency be increased in energy transfer?

  By using a plastic lid
• What does higher thermal conductivity mean?

  Higher rate of energy transfer by conduction
• Why do builders use insulating materials?

  To reduce thermal energy transfer through walls
• What is the difference between double glazed and single glazed windows?

  Double glazed has low thermal conductivity
• How can thermal energy escape from a house be reduced?

  By using materials with low thermal conductivity
• What are the steps in the required practical for specific heat capacity?

  1. Place beaker on balance and zero it
  2. Add oil and record mass
  3. Insert thermometer and immersion heater
  4. Read starting temperature
  5. Wrap beaker in insulating foam
  6. Connect joulemeter to immersion heater
  7. Time for 30 minutes
  8. Read joules and final temperature
• What is a reason for inaccuracy in measuring specific heat capacity?

  Thermal energy passing out of the beaker
• How can thermal energy loss be minimized?

  Use an insulator with lower thermal conductivity
• What are fossil fuels?

  Coal, oil, and gas
• What are the advantages of fossil fuels?

  Reliable, abundant, and cheap energy source
• What are the disadvantages of fossil fuels?

  Release carbon dioxide and are non-renewable
• What is a disadvantage of nuclear power?

  Generates large amounts of radioactive waste
• What is the UK energy mix historically based on?

  Burning coal for electricity generation
• Why did the UK switch from coal to gas?

  Gas generates less carbon dioxide
• What are renewable energy resources?

  Resources that can be replenished
• What are the advantages of renewable energy?

  Do not add carbon dioxide and never run out
• What is a disadvantage of wind and solar power?

  They are not reliable energy sources
• What is geothermal energy used for?

  Generating electricity and heating buildings
• What is biomass energy?

  Energy produced from plants
• What is a concern with using land for biofuels?

  It could push up food prices
• What are the disadvantages of renewable energy sources?

  • Wind and solar power are not reliable
  • Hydroelectric can destroy habitats
  • Tidal power is not utilized in the UK
  • Wave power is experimental and small scale