Energy

• Give some examples of energy stores

  • Chemical
  • Kinetic
  • Gravitational
  • Thermal
  • Elastic
  • Magnetic
  • Electrostatic
  • Nuclear
• What is the difference between an energy store and and energy pathway

  An energy store is when energy can be stored for a measurable amount of time
• What is the law of conservation of energy?

  "Energy can be transferred usefully, stored or dissipated, but cannot be created or destroyed"
• What is the equation linking kinetic energy, mass and velocity?

  Kinetic energy = 0.5 x mass x (speed)2
• What are the units for velocity?

  m/s
• What are the units for mass?

  kg
• What are the units for kinetic energy?

  J or Joules
• What is elastic potential energy?

  the energy stored in an elastic object
• What is equation linking elastic potential energy, the spring constant and extension?

  elastic potential energy = 0.5 × spring constant × (extension)2
• What are units for elastic potential energy?

  J or Joules
• What are the units for the spring constant?

  N/m or Newtons per metre
• What are the units for extension?

  m or metres
• What is gravitational potential energy?

  energy gained by an object raised above ground level
• What is the equation linking gravitational potential energy, mass, gravity and height?

  g.p.e. = mass × gravitational field strength × height
• What are the units for gravitational potential energy?

  J or Joules
• What is the value and the units for gravity?

  N or Newtons
• What are the units for height?

  m or metres
• What does this symbol mean Δ?

  change in
• What is specific heat capacity?

  the amount of energy required to raise the temperature of one kilogram of the substance by one degree Celsius
• What is the equation linking changing energy, mass, specific heat capacity and change in temperature?

  change in thermal energy = mass × specific heat capacity × temperature change
• What are the units for energy?

  J or Joules
• What are the units for specific heat capacity?

  J/kg °C
• What are the units for change in temperature?

  °C
• What is power?

  the rate at which energy is transferred or the rate at which work is done
• What is the equation linking power, energy and time?

  Power = energy transferred ÷ time
• What are the units of power?

  W or watts
• What are the units for time?

  s or seconds
• What is the equation linking power, work done and time?

  power = work done ÷ time
• What is 1 joule per second equal to?

  1 watt
• What are the units for work done?

  J or Joules
• What happens to waste energy?

  dissipates to the surroundings
• How can we reduce wasting energy?

  through lubrication and the use of thermal insulation.
• Give three examples of insulation that can be used in the house

  • double glazed windows
  • loft insulation
  • cavity wall insulation
• What is the equation for working out efficiency?

  
  

  Efficiency = useful power output ÷ total power input
• What are the units for efficiency?

  There are no units
• What are the main energy resources on Earth?

  • fossil fuels (coal, oil and gas)
  • nuclear fuel
  • biofuel
  • wind
  • hydro-electricity
  • geothermal
  • The tides & water Waves
  • the Sun
• What is a renewable resource?

  one that is being (or can be) replenished as it is used.
• What is finite resource?

  one that cannot be replenished as it is used within our lifetime
• What are the different types of energy pathways?

  Light, sound, Radiation, mechanical, electrical, by heating