Conservation of energy P3

• What is a renewable energy resource?

  An energy source that can be replenished
• What are the advantages of generating power using gas rather than coal?

  Gas has flexible generation and lower emissions
• What are two disadvantages of using renewable energy resources to generate power?

  • Supply is uncertain due to external factors
  • Renewable fuels produce less energy per kg
• What are the environmental impacts of burning fossil fuels?

  Contributes to greenhouse effect and acid rain
• What are three advantages of fossil fuels as an energy resource?

  • Reliable and can generate power anytime
  • Produce large amounts of energy per kg
  • Relatively abundant and cost-effective
• What are three advantages of nuclear power?

  • Very large amounts of energy per kg
  • No greenhouse gases released
  • Low fuel costs
• What are three disadvantages of nuclear power?

  • Produces harmful nuclear waste
  • Non-renewable energy source
  • Risk of nuclear accidents
• How does hydroelectric power produce energy?

  • Rainwater collects behind a dam
  • Water turns a turbine
  • Turbine turns a generator to produce electricity
• What are some disadvantages of using biofuels?

  • CO2 released when plants are burned/decay
  • Habitat destruction for growing biofuels
  • Reduces land available for food crops
• What are the advantages of tidal energy sources?

  • No greenhouse gases
  • Fairly reliable due to tides
  • Cheap to run as tides are natural
• What is the equation for gravitational potential energy?

  mgh
• What are the disadvantages of hydroelectric power?

  • The dam may cause flooding
  • High installation costs for infrastructure
• What does each variable in the equation mgh represent?

  Mass, gravitational field strength, height
• What are the SI units for energy?

  Joules (J)
• What are some advantages of solar panels?

  • Do not harm the environment
  • Renewable resource
  • Usable in remote areas
• What is the equation for kinetic energy?

  ½ mv²
• What does the equation ½ mv² represent?

  Kinetic energy of an object
• What are the SI units for kinetic energy?

  Joules (J)
• What is meant by the conservation of energy?

  Total energy in a closed system remains constant
• What are the key points of conservation of energy?

  • Total energy remains constant in a closed system
  • Energy cannot be created or destroyed
  • Energy can change forms
• Describe the energy changes when a ball is thrown upwards.

  KE converts to GPE as it rises
• What happens to energy at the peak of the ball's throw?

  Maximum GPE, zero KE
• Describe the energy changes when the ball returns downwards.

  GPE converts to KE as it falls
• What happens to the total energy of a kicked ball?

  Total energy remains constant due to conservation
• What energy changes occur in a filament light bulb?

  Electrical energy converts to light and heat
• Describe the energy transfers for a bungee jumper.

  GPE converts to KE, then to EPE
• Why does a bungee jumper slow down when the cord stretches?

  KE decreases as it converts to EPE
• What is waste energy?

  Energy not used for its intended purpose
• What is one equation to calculate efficiency?

  Useful Output Energy / Total Input Energy
• What is another equation to calculate efficiency?

  Useful Power Output / Total Power Output
• What is the consequence of high thermal conductivity?

  Higher rate of energy transfer
• Do double-glazed windows have higher or lower thermal conductivity?

  Lower thermal conductivity
• What are three methods to reduce heat loss in a building?

  1. Double glazing
  2. Loft and wall insulation
  3. Thicker walls
• How can you reduce unwanted energy transfer in a mechanical system?

  Reduce friction by lubricating parts
• How can the efficiency of a system be increased?

  1. Reduce waste output (lubrication, insulation)
  2. Recycle waste output (thermal waste as input)