work, energy an power

• what are the energy transfers

  electrical, mechanical, heating and waves
• what is electrical transfer

  when charge flows to produce an electric current
• what is mechanical transfer

  when a force is applied to move an object
• what is heating transfer

  when the internal energy of an object is determined by the temperature of the object
• what is wave transfer

  When sound travels through a material it causes the particles to vibrate
• what are the energy changes in an electrical heater

  electrical -> thermal + sound + light
• what are the energy changes in a gas cooker

  chemical -> thermal + light + sound
• what are the energy changes in a falling object

  gpe -> kinetic
• what are the energy changes in a horizontal mass on a spring

  elastic potential -> kinetic energy
• how do you calculate a loss in kinetic energy on an object travelling up a rough inclined surface

  loss in Ek = gain in gpe + work done against friction
• what is work done

  the transfer of energy when an external force causes an object to move over a certain distance
• how do you calculate work done

  force x displacement
• how do you calculate work done if the force is at an angle to the object's displacement

  force x displacement x cos
• how do you write kinetic energy in terms of momentum

  momentum^2 / 2m
• what is mechanical energy

  the sum of kinetic energy, gravitational potential energy and elastic potential energy
• in terms of the principle of conservation of energy, what does a loss in gravitational potential energy mean

  a gain in kinetic energy or a gain in elastic potential energy
• what is power

  the rate of work done (energy transfer)
• what is an equation for power f

  force x velocity
• what is efficiency

  The ratio of the useful power or energy transfer output from a system to its total power or energy transfer input
• what is energy density

  a measure of the amount of energy per unit volume of a fuel