Physics CP03 Conservation of Energy

• How is energy transferred differently from energy stored?

  Energy transferred involves moving energy from one place to another, while energy stored is held in a system.
• When might energy be transferred while energy is stored?

  Energy can be transferred while stored when it is released for use, such as in a battery.
• What are the different types of energy?

  Types of energy include thermal, kinetic, gravitational potential, elastic potential, chemical, and nuclear energy.
• What can you say about the total amount of energy in a closed system?

  The total amount of energy in a closed system remains constant.
• What is thermal energy?

  Thermal energy is energy stored as heat.
• What is kinetic energy?

  Kinetic energy is energy stored in objects that can move.
• What is gravitational potential energy?

  Gravitational potential energy is energy stored in objects that can fall.
• What is elastic potential energy?

  Elastic potential energy is energy stored in objects that can be stretched.
• What is chemical energy?

  Chemical energy is energy stored in fuels.
• What is nuclear energy?

  Nuclear energy is energy stored in the nucleus of atoms.
• Describe the changes in energy stores when a car accelerates.

  As a car accelerates, chemical energy in the fuel is converted to kinetic energy.
• What happens to the kinetic energy of a ball thrown upwards as it goes up and then down?

  The kinetic energy decreases as it goes up and increases as it comes down.
• If some of the energy in a closed system is transferred to the surroundings, what happens to the overall energy in the system?

  The overall energy in the system decreases by the amount transferred.
• List the ways in which energy can be transferred.

  Energy can be transferred by doing work, heating, or electrical current.
• What is the law of conservation of energy?

  The law of conservation of energy states that energy cannot be created or destroyed, only transferred.
• What does an energy transfer diagram illustrate?

  An energy transfer diagram illustrates how energy is stored and transferred in a system.
• What does a Sankey diagram represent?

  A Sankey diagram shows the amount of energy transferred, with the width of the arrow representing energy in joules.
• How much energy was wasted when 1000 J of energy is transferred to a kettle and 500 J is used up in boiling water?

  500 J of energy was wasted in the process.
• How would the energy transfer diagram differ for a car hitting a wall?

  The diagram would show a significant loss of kinetic energy due to the impact.
• Describe the energy stores and transfers when someone switches on a light.

  When a light is switched on, electrical energy is input and transformed into light and thermal energy as output.
• How does geothermal energy produce electricity?

  Geothermal energy harnesses heat from the Earth's core to generate steam that spins turbines.
• What are the drawbacks of solar cells?

  Solar cells do not produce energy at night or when it is cloudy, and their efficiency is affected by the angle of the sun.
• How is hydroelectricity produced?

  Hydroelectricity is produced by letting water flow through pipes that spin a turbine.
• What is the process of wind energy generation?

  Wind energy generation involves wind spinning the blades of a turbine, which rotates a shaft connected to a generator.
• What is tidal power?

  Tidal power generates electricity when water flows in and out of tidal basins, moving a turbine that drives a generator.
• What are the advantages of renewable energy resources?

  Renewable energy resources will not run out and can be used to generate electricity and heat.
• What are the disadvantages of using geothermal energy?

  Disadvantages of geothermal energy include high costs and the potential for induced seismicity.
• How does the use of renewable energy change over time?

  The use of renewable energy has increased as technology improves and awareness of environmental issues grows.
• Why is it important to properly decommission nuclear power stations?

  Proper decommissioning is important to ensure safety and manage radioactive waste effectively.
• What are the effects of using non-renewable resources?

  Using non-renewable resources can lead to environmental degradation and contribute to climate change.
• How do non-renewable resources run out?

  Non-renewable resources run out due to their finite nature and increasing consumption rates.
• What is one advantage of using fossil fuel power stations?

  One advantage of fossil fuel power stations is their ability to generate large amounts of energy quickly.
• What is one disadvantage of using fossil fuel power stations?

  One disadvantage of fossil fuel power stations is their contribution to greenhouse gas emissions.
• What is the significance of the energy resources used for generating electricity in the UK since 1970?

  The significance lies in the shift towards more renewable energy sources and reduced reliance on fossil fuels.
• How can renewable energy be used to meet our needs?

  Renewable energy can be used to generate electricity, heat, and fuel for transport.
• How is the use of renewable energy changing?

  The use of renewable energy is increasing due to technological advancements and environmental awareness.
• What happens to the kinetic energy when an object hits the ground?

  The kinetic energy is transformed into other forms of energy, such as sound and thermal energy, upon impact.
• How can you calculate gravitational potential energy?

  Gravitational potential energy can be calculated using the equation $GPE =$$mgh$.
• What is the value of $g$ on Earth's surface?


  The value of $g$ is usually taken as $9.8 \text{ N/kg}$.
• Calculate the gravitational potential energy of a 2 kg bag of flour raised to a height of 1 m using $g =$$9.8 \text{ N/kg}$.


  The GPE is $19.6 \text{ J}$.