Energy

• How many different energy stores are mentioned in the video?

  Eight
• What are the eight different energy stores that need to be remembered?

  Kinetic, thermal, gravitational potential, elastic potential, chemical, electrostatic, magnetic, and nuclear
• Which energy stores are more common and should be focused on?


  The ones that are more recognizable
• What is the equation for kinetic energy?

  E = \frac{1}{2} mv^2
• What does the equation for gravitational potential energy represent?

  E = mgh, where m is mass, g is gravitational field strength, and h is height
• What are the units for gravitational field strength?

  Newtons per kilogram or meters per second squared
• What is elastic potential energy related to?

  When things are being stretched or compressed
• What is the definition of specific heat capacity?

  The energy required to increase the temperature of one kilogram of a substance by one degree Celsius
• What is the equation for calculating the change in energy using specific heat capacity?

  Change in energy = mass × specific heat capacity × temperature change
• How can the specific heat capacity equation be rearranged?

  To isolate specific heat capacity on one side
• What is the principle of conservation of energy?

  Energy can never be created or destroyed, only transferred, stored, or dissipated
• What does power represent in physics?

  The rate of doing work
• How does conduction occur?

  Through the vibration of particles in solids
• What is convection and where does it occur?

  Convection occurs in liquids and gases as particles spread out when heated
• What are some methods to reduce unwanted energy transfers?

  Cavity wall insulation, loft insulation, draft excluders, and double glazed windows
• What does the efficiency equation represent?

  The ratio of useful output energy to total input energy
• What is the significance of the National Grid?

  It distributes electricity from power stations to homes using transformers
• What is the role of a step-up transformer in the National Grid?

  To increase voltage and reduce energy loss as heat during transmission
• What happens at the step-down transformer in the National Grid?

  It decreases the voltage to a safe level for household use
• What are the pros and cons of renewable energy resources?

  Pros:

  • Never run out
  • Less environmental damage

  
  

  Cons:

  • Can be unreliable (e.g., solar power in cloudy regions)
  • May disturb habitats (e.g., building dams)
• What are the pros and cons of non-renewable energy resources?

  Pros:

  • Generally more reliable
  • Established technology

  
  

  Cons:

  • Finite resources (will run out)
  • Environmental damage (e.g., fossil fuel extraction)
• What is kinetic energy?

  Kinetic energy is the energy stored in moving objects.
• Why does a stationary object like a parked car have no kinetic energy?

  Because it is not moving.
• What are the units for mass and speed in the kinetic energy formula?

  Mass is in kilograms and speed is in meters per second.
• What energy changes occur when a car runs on petrol?

  • Chemical energy stored in petrol
  • Chemical reaction in the engine
  • Conversion of chemical energy to kinetic energy as the car moves
• How do scientists often convert joules into kilojoules?

  By dividing by 1,000.
• What should you be able to do by the end of the video on kinetic energy?

  • Describe what is meant by kinetic energy
  • Calculate kinetic energy for a moving object
• What is elastic potential energy?

  Energy stored in a stretched spring
• What is the formula to calculate elastic potential energy?

  Elastic potential energy = 0.5 × spring constant × extension^2
• If a spring has an extension of 20 cm, what is the first step to calculate elastic potential energy?

  Convert the extension from centimeters to meters
• How do you convert 20 cm to meters?

  Divide by 100 to get 0.2 m
• What is gravitational potential energy?

  It is the energy stored in an object due to its position above the Earth's surface
• What is the formula to calculate gravitational potential energy?

  Gravitational potential energy (J) = mass (kg) × gravitational field strength (N/kg) × height (m)
• What is the unit of gravitational potential energy?

  Joules (J)
• Why is the gravitational field strength important in the calculation of gravitational potential energy?

  It measures the force of gravity acting on the object
• What is the gravitational field strength value given in the sample question?

  1. 8 Newtons per kilogram
• How do you convert 500 grams to kilograms?

  By dividing by 1,000, so 500 g = 0.5 kg
• Mechanical Work


  A type of energy transfer due to force applied over a distance.
• Joules


  The unit of work, measuring the energy transferred.
• Work Done when a current flows


  The energy is equal to the potential difference multiplied by the current times by the time.