Physics paper 1

• moon- 1.6 newtons/kg
• gravity is a non contact force because the objects dont need to be touching
• gravity has a magnitude and direction
• mass


  how much matter the object has in it
• weight

  force acting on it due to gravity
• conduction

  vibrating particles transfer energy to neighbouring particles
• conduction occurs mainly in solids
• thermal conductivity

  how well objects transfer energy
• convention occurs mainly in fluids

  (liquids and gases )
• reduce convection

  stop the free flow of fluids
• conduction

  only energy is transferred

  gains kinetic energy
• convection 


  the particles move

  gains kinetic energy
• internal energy

  the total energy stored by the particles making up a substance or system
• potential energy store

  1. gravitational
  2. elastic
• specific heat capacity

  1. the amount of energy needed to raise the temperature of 1kg of a substance by 1 degree celcius
• water

  4200J/kg*c
• conservation of energy principle

  energy can be transferred usefully , stored or dissipated but can never be create or destroyed
• friction 


  the resistance that one object encounters when moving over a solid or through a liquid
• power 


  the rate at which energy is transferred
• power is the rate at which work is done
• efficiency

  proportion of the energy supplied that’s transferred to the useful energy output
• efficiency = useful energy output divided by total energy input
• efficiency = useful power output divided by total power input
• renewable resources

  1. wind
  2. solar
  3. hydroelectric
  4. geothermal
  5. tidal
  6. biofuels
• non renewable resources

  1. coal
  2. crude oil
  3. natural gas
  4. nuclear energy
• A fossil fuel is a hydrocarbon containing material formed naturally in the earths crust from the remains of dead plants and animals
• fossil fuels

  1. coal (solid)
  2. crude oil (liquid)
  3. natural gas (gaseous )
• pros of fossil fuels

  1. relatively cheap
  2. can be used in any condition
  3. much of our infrastructure is designed to run using fossil fuels
• cons of fossil fuels

  1. they’re a limited resources so will run out one day
  2. they produce carbon dioxide when burned which is a greenhouse gas and contributes to global warming
• nuclear energy is energy obtained via nuclear reactions such as nuclear fission reactions in nuclear power stations
• pros of nuclear energy

  1. nuclear fuels do not produce any pollutants or greenhouse gases like CO2 or sulfur dioxide
  2. can be used in any condition
  3. it’s unlikely to run out
• cons of nuclear energy

  1. technically a finite resource
  2. nuclear power stations produce radioactive waste which remains harmful for thousands of years
  3. its expensive
• geothermal energy is thermal energy generated and stored in the earths crust
• biofuels

  fuels thats made from recently living organisms
• advantages of biofuels

  1. cheap to make
  2. a renewable resource
  3. easy to transport
  4. mix them with fossil fuels
• disadvantages of biofuels

  1. they require a lot of energy to harvest, process and transport
  2. they require a large area of land to grow
• hydroelectric dams

  1. trapping water that comes from upstream
• tidal barrages

  1. making use of tides
• pros of hydroelectric dams and tidal barrages

  1. large amounts of energy with no pollution
  2. reliable sources of electricity
  3. running costs are fairly low
• cons of hydroelectric dams and tidal barrages

  1. often have a big impact on the surrounding environment
  2. often flood huge areas because of their size
  3. sometimes stop boats and fish from travelling
  4. expensive