Energy

• What is energy stored in different energy stores referred to as?

  Energy is transferred between different energy stores and objects.
• What happens when energy is transferred to an object?

  The energy is stored in one of the object’s energy stores.
• What are the common types of energy stores mentioned?

  • Kinetic energy store
  • Gravitational potential energy store
  • Elastic potential energy store
• How does movement relate to an object's kinetic energy store?

  Anything that is moving has energy in its kinetic energy store.
• What factors affect the energy in an object's kinetic energy store?

  The energy depends on the object's mass and speed.
• What is the formula for calculating kinetic energy?

  $E_k =$$\frac{1}{2}mv^2$
• Calculate the kinetic energy of a car with a mass of 2500 kg traveling at 20 m/s.

  $E_k =$$\frac{1}{2} \times 2500 \times 20^2 =$$500,000 \text{ J}$
• What happens when an object is lifted in a gravitational field?

  It requires work, causing a transfer of energy to the gravitational potential energy store.
• What factors determine the amount of energy in a gravitational potential energy store?

  The energy depends on the object's mass, height, and the strength of the gravitational field.
• What is the formula for calculating gravitational potential energy?

  $PE =$$mgh$
• What occurs when an object falls without air resistance?

  Energy lost from the gravitational potential energy store equals energy gained in the kinetic energy store.
• How does air resistance affect falling objects?

  It causes some energy to be transferred to other energy stores, like thermal energy stores.
• What happens when an object is stretched or squashed?

  Energy is transferred to its elastic potential energy store.
• What is the formula for calculating elastic potential energy?

  $E =$$\frac{1}{2}ke^2$
• What is the limit of proportionality in relation to elastic potential energy?

  It is the point beyond which the elastic potential energy cannot be accurately calculated.
• What should you remember about the energy in an object's kinetic energy store?

  • It only changes if the object's speed changes.
  • Kinetic energy is dependent on mass and speed.
• What is the principle of conservation of energy?

  Energy is always conserved and cannot be created or destroyed.
• What happens to energy when it is transferred between stores?

  Not all energy is transferred into the desired store; some is always dissipated.
• Why is dissipated energy sometimes called 'wasted energy'?

  Because it is stored in a way that is not useful, often as thermal energy.
• What is power defined as?

  Power is the rate of energy transfer or the rate of doing work.
• How is power measured?

  Power is measured in watts.
• What are the methods to reduce unwanted energy transfers?

  • Lubrication reduces frictional forces.
  • Thermal insulation reduces the rate of energy transfer by heating.
• How does lubrication help in energy transfer?

  Lubrication reduces frictional forces acting against moving objects.
• What is the effect of thermal insulation on energy transfer?

  Thermal insulation reduces the rate of energy transfer by heating.
• What is one way to prevent thermal conduction in buildings?

  Use thick walls made from materials with low thermal conductivity.
• How do cavity walls help in thermal insulation?

  Cavity walls have an air gap that reduces energy transfer by conduction.
• What materials are commonly used for thermal insulation in buildings?

  Expanded polystyrene and mineral wool are used as insulating materials.
• How can you investigate the effectiveness of materials as thermal insulators?

  By measuring the temperature change of water in a container wrapped in different materials.
• What does a smaller temperature difference indicate in terms of thermal insulation effectiveness?

  A smaller temperature difference indicates better thermal insulation.
• What happens to energy transfer as the thickness of the insulating material increases?

  The thicker the insulating layer, the smaller the temperature change and less energy is transferred.
• What are the major uses of energy resources?

  • Generating electricity
  • Heating
  • Transport
  • Building
• What are non-renewable energy resources?

  Non-renewable energy resources include fossil fuels and nuclear fuel.
• What are the three main fossil fuels?

  The three main fossil fuels are coal, oil, and natural gas.
• What is a characteristic of renewable energy resources?

  Renewable energy resources will never run out.
• What are some examples of renewable energy resources?

  Examples include solar, wind, water power, hydro-electricity, bio-fuel, tidal, and geothermal energy.
• How does hydro-electric power generate electricity?

  Hydro-electric power uses falling water to turn turbines.
• What is a drawback of hydro-electric power?

  It can have a significant environmental impact due to flooding.
• What is wave power?

  Wave power uses small wave-powered turbines located along the coast to generate electricity.
• What is a disadvantage of wave power?

  It can disturb the seabed and marine habitats.
• What is geothermal power derived from?

  Geothermal power is derived from underground thermal energy stores.