Physics unit 4

• What is the unit for mass?

  kilogram (kg)
• What is the unit for energy?

  joule (J)
• What is the unit for distance?

  metre (m)
• What is the unit for speed?

  metre/second (m/s)
• What is the unit for acceleration?

  metre/second² (m/s²)
• What is the unit for force?

  newton (N)
• What is the unit for time?

  second (s)
• What is the unit for power?

  watt (W)
• What are the types of energy stores?

  • Chemical
  • Kinetic
  • Gravitational
  • Elastic
  • Thermal
  • Magnetic
  • Electrostatic
  • Nuclear
• What are the methods of energy transfer?

  • Mechanically
  • Electrically
  • By heating
  • By radiation (light and sound)
• What does the principle of conservation of energy state?

  Energy cannot be created or destroyed
• How is efficiency calculated?

  Efficiency = useful energy output / total energy output

  
• What does a Sankey diagram represent?

  Energy transfers and efficiency visually

  
• How does thermal energy transfer occur?

  • Conduction
  • Convection
  • Radiation

  
• What is conduction?

  Transfer of thermal energy through solids
• What is convection?

  Transfer of thermal energy through fluids
• What is radiation in terms of thermal energy transfer?

  Transfer of thermal energy via infrared waves
• How does surface and temperature relate to emission and absorption of radiation?

  Dark surfaces absorb and emit better
• What is the relationship between temperature and radiation absorption?

  Higher absorption leads to higher temperature
• What is the role of insulation in energy transfer?

  Reduces unwanted energy transfer
• What is work in physics?

  Energy transferred when a force acts
• What is the relationship between work done and energy transferred?

  Work done equals energy transferred
• How is gravitational potential energy calculated?

  Using mass, height, and gravitational field strength

  
• What is power in terms of energy?

  Rate of transfer of energy or work

  
• How is power calculated?

  Power = work done / time taken

  
• What are the advantages and disadvantages of energy production methods?

  Advantages:

  • Renewable resources are sustainable
  • Non-renewable resources are efficient

  
  

  Disadvantages:

  • Renewable resources can be variable
  • Non-renewable resources are finite
• What is the definition of energy?

  Ability to do work
• What is the definition of work?

  Energy transferred between stores
• What is the definition of efficiency?

  Measure of useful energy output

  
• What is the definition of power?

  Rate of doing work
• What happens to thermal energy in terms of dissipation?

  It spreads out and becomes wasted
• How does the density of a metal affect its thermal conductivity?

  Denser metals conduct heat better
• What is the purpose of cavity wall insulation?

  To reduce heat transfer through walls
• How does a vacuum flask reduce thermal energy transfer?

  It prevents conduction and convection
• What is the role of the reflective coating in a vacuum flask?

  Reflects infrared radiation to maintain temperature

  
• What is the impact of a good insulator in a vacuum flask?

  Reduces conduction and convection
• What happens to water molecules during convection heating?

  They gain kinetic energy and rise
• What is the effect of heating on the density of water?

  Hot water becomes less dense and rises
• How does a land breeze occur at night?

  Cool air from land replaces rising warm air

  
• What is the greenhouse effect?

  Trapping heat in the Earth's atmosphere