Energy

• Nine types of energy

  1) Electrical

  2) Light

  3) Sound

  4) Kinetic or Movement

  5) Nuclear

  6) Thermal or Heat

  7) Gravitational Potential

  8) Elastic Potential

  9) Chemical
• Principle of conservation of energy


  Energy can never be created nor destroyed - it is only ever transferred drom one form to another
• Energy


  Energy exists in many forms - heat, light etc.

  It is required to do work
• Energy Efficiency


  Energy is only useful when it can be transferred from one form to another

  The less energy that is wasted, the more efficient the device is said to be
• Efficiency


  A measure of how much effectively energy is transformed into a useful form
• Efficiency (formula)


  Useful Energy output / Total Energy input
• Work


  The transfer of energy to a body. Mechanical work is the transfer of energy which occurs when a force is applied through a distance in the direction of force
• Work (2)


  When a force moves an object, energy is transferred and work is done
• Work done (J) (formula)

  Force (N) x Distance moved (m)
• Power


  The rate of transfer or conversion of energy

  Rate of "doing work"
• Power (J/s or W) (formula)

  Work done (J) / Time taken (s)
• Kinetic energy (J) (formula)

  1/2 x mass (kg) x speed^2 (m/s^2)
• GPE


  Mass (kg) x gravity (10 m/s^2) x height (m)
• Falling objects convert GPE into KE

  KE gained = GPE lost
• Electrical energy


  Energy made available by the flow of electric charge through a conductor
• Light energy


  Energy in the form of moving waves of light
• Sound energy


  energy carried by sound waves
• Kinetic Energy


  Energy of motion
• Nuclear Energy


  The potential energy stored in the nucleus of an atom
• Thermal Energy


  The total energy of motion in the particles of a substance
• Gravitational Potential Energy


  Potential energy that depends on the height of an object
• Elastic Potential Energy


  The potential energy of an object that is stretched or compressed
• Chemical Energy


  potential energy stored in chemical bonds
• what is kinetic energy?


  the energy of a moving object
• What is gravitational potential energy?


  the energy of an object at height e.g. a stone held up in the air can do work when dropped because gravity will pull it downwards
• what is chemical energy?

  The energy stored in chemical bonds, such as those between molecules
• What is electrostatic energy?

  The energy stored when repelling charges have been moved close together or when attracting charges have been pulled further apart.
• What is elastic potential energy?

  the energy stored when an object is stretched or squashed
• What is internal/thermal energy?

  the total kinetic and potential energy of the particles in an object, in most cases this is the vibrations - also known as the kinetic energy - of most particles. In hotter objects, the particles have more internal energy and vibrate faster.
• what is nuclear energy?


  the energy stored in the nucleus of an atom
• what is magnetic energy?

  the energy stored when repelling poles have been pushed closer together or when attracting poles have been pulled further apart.
• what are the units of energy?

  Joules (J)
• What is the law of conservation of energy?

  Energy cannot be created or destroyed, it can only be transferred from one type to another.
• what is work?


  a word which means transfer of energy
• what are the different ways of transferring energy from one store to another?

  mechanically, electrically and by heating or raditation
• what is the gravitational field strength on earth?

  10N/kg
• GPE =


  mgh
• Weight =


  Mass x gravitational field strength
• KE =


  1/2mv^2
• what else does KE =? vice versa

  GPE