Energy !

• Law of conservation of Energy = Energy cannot be created or destroyed. It is only transferred from one store to another.
• Kinetic energy = The energy stored in a moving object
• Gravitational potential energy (GPE) = The energy stored in an object that is lifted above ground, in the gravitational field
• Elastic potential energy = The energy stored when an object is stretched, squashed or twisted
• Magnetic energy = The energy stored when repelling poles are pushed closer together or attracting poles are pulled further apart
• Chemical energy = The energy stored in chemical bonds between atoms in fuels, food and batteries
• Electrostatic energy = The energy stored when repelling charges are pushed closer together or attracting poles are pulled further apart
• Thermal energy = The energy stored when an object is warm or hot
• Nuclear energy = The energy stored in the nucleus of an atom
• Transfer pathways:

  • Mechanically
  • Electrically
  • Force (e.g gravity)
  • Heating
  • Raditation
• True or false: Light and sound ARE transfer pathways

  False
• A system is the object we have when energy transfer takes place
• A system is an object or a group of objects
• Energy can be stored or transferred
• When a 'system' changes, energy is transferred either: into or away from the system between different objects in the system between different types of energy stores
• A 'closed system' is a system where neither matter nor energy can enter or leave
• The net change in the total energy of a closed system is 0
• The unit and unit symbol for all types of energy is Joules,J
• An example of energy stored as elastic potential energy is stretched or compressed spring
• An example of energy stored as thermal energy is a property an object has because of the kinetic energy of its particles (so everything has a thermal energy store)
• Another name for a thermal energy store is an Internal energy store
• An example of energy stored as kinetic energy is anything that is moving
• An example of energy stored as gravitational potential energy is any object above the ground
• An example of energy stored as chemical energy is an object that has energy stored due to its chemical composition - e.g batteries,fuels,food
• An example of energy stored as electrostatic energy is between two charged objects (i.e. two objects that have a potential difference)
• An example of energy stored as nuclear energy is a radioactive nuclei
• The 4 main ways energy can be transferred between energy stores are: Heating, radiation, electrical working and mechanical working
• An example of how energy is transferred mechanically is a force doing some work
• How is energy transferred by radiation?

  Waves are given out in all directions
• An example of how energy is transferred through radiation is light & sound, or anything that is part of the EM spectrum
• An example of how energy is transferred electrically is a complete circuit allowing charge to flow
• What are the energy store changes when a ball is thrown upwards?

  • Kinetic energy store = decreases
  • Gravitational potential energy store = increases
• Another way of saying 'energy transferred' is 'Work done'
• What two measurements do you need to be able to calculate the kinetic energy store of a moving object?

  Mass (in metres,m) & velocity (in metres per second, m/s)
• What is the word equation for calculating kinetic energy?

  1/2 × mass × velocity$^2$
• What is the symbol equation for kinetic energy

  KE = ½ × m × v2
• What is the word equation for calculating gravitational potential energy?

  GPE = mass × gravitational field strength (9.8) × height
• What is the symbol equation for calculating gravitational potential energy?

  Ep = mgh
• When an object is falling, stored gravitational potential energy is transferred to its kinetic energy store
• What 2 ways can elastic potential energy be transferred to an object?

  Stretching or squashing