physics

• describe what a system is.


  an object or a group of objects
• what is the energy store change for a football that has been kicked upwards?

  as the ball moves upwards, the kinetic energy of the ball decreases and the gravitational potential of the ball increases
• What is the equation linking kinetic energy, mass and speed?


  Kinetic energy = 1/2 x mass x speed^2
• units for kinetic energy?


  Joules
• Units for mass?


  Kilograms
• Units for speed?


  Meters per second
• Equation linking elastic potential energy, spring constant and extension?

  Elastic potential energy =

  0.5 x spring constant x extension^2
• Equation linking gravitational potential energy, mass, gravitational field strength and height?


  Gravitational potential energy = mass x gravitational field strength x height
• equation linking change in thermal energy, mass, specific heat capacity and temperature change?

  change in thermal energy =

  Mass x specific heat capacity x temperature change
• units for spring constant

  Newtons per meter
• Units for extension 


  Meters
• Units for elastic potential energy?


  Joules
• units for gravitational energy?


  Joules
• units for gravitational field strength?

  Newton per kilogram (N/kg)
• define power.


  power is the amount of energy transferred per second
• Write a definition for specific heat capacity.

  the heat which can increase one unit temperature as of a mass unit of a substance
• units for power?


  Watts
• Units for energy transferred?


  Joules
• Units for time?


  Seconds
• Units for work done?

  Joules
• what is the law of conservation of energy?

  Energy cannot be created or destroyed, only transferred or transformed from one form to another.
• Define dissipation.


  dissipation is a term thats used to describe ways in which energy is wasted.
• Describe how thermal conductivity of a material affects how it transfers energy by conduction.

  if a material has a high thermal conductivity it will transfer heat via conduction at a quicker speed rate.
• How is energy lost through a building, what could affect this?

  Heat loss. Factors affecting it include insulation quality, air leakage, windows, and doors.
• Equation linking efficiency, useful output energy transfer and total input energy transfer?

  Efficiency = useful power divided by total energy
• equation linking efficiency, useful power output and total power input?

  Efficiency = useful power divided by total energy
• when energy is transferred in a closed system, what happens to the total amount of energy?

  there is no net change.
• How can the efficiency of an energy transfer be increased?

  Insulation
• Define renewable resource?


  A resource that can be replenished.
• Define non renewable resource?

  limited supply
• What is electric current?

  Flow of electric charge.
• What is the equation linking charge flow, current and time?

  charge flow = current x time
• units for charge flow?

  Coulombs
• Units for current?


  Amperes
• Equation linking current, potential difference and resistance?

  current x resistance
• Energy cannot be created or destroyed
• Dissipation


  The process of energy being spread out or wasted
• Energy can be transferred, stored, or dissipated
• Main energy resources


  • Coal
  • Oil
  • Gas
  • Nuclear
  • Biofuel
  • Wind
  • Hydroelectricity
  • Geothermal
  • Tidal
  • Waves
  • Solar
• Energy transfers in a television

  1. Useful: chemical energy stores

  2. Light and sound carry energy to surroundings

  3. Energy dissipated: thermal energy stores of surroundings