energy changes

• a system is an object or group of objects
• sankey diagrams illustrate how energy is distributed
• Ek (kinetic energy) $\frac{1}{2}mv^2$
• gravitational potential

  $E_p=$$mgh$
• internal energy is the total kinetic and potential energy of all the particles in a system
• doing work on a system increases the energy stored
• if a temperature increases, it depends on:

  • mass
  • what the substance is
  • energy input
• amount of energy stored can be found by work done using the calculation force*distance
• energy can be transferred usefully, stored or dissipated
• energy cannot be created or destroyed
• renewable energy sources can be replenished
• non-renewable recourcses will eventually run out
• specific heat capacity

  • $\Delta E\ =$$\ mc\Delta\theta$
  • change in thermal energy = (mass)(specific heat capacity)(change in temperature)
• elastic potential energy

  $E_e=$$\frac{1}{2}ke^2$

  
  

  k- spring constant

  e- extention
• unwanted energy transfers can be reduced by:

  • lubrication - reduces friction that produces heat
  • tightening loose parts - prevent unwanted vibrations so theres no energy waste as sound
  • thermal insulation - reduces heat loss
• unwanted energy transfers can be reduced by:

  • lubrication - reduces friction that produces heat
  • tightening loose parts - prevent unwanted vibrations so theres no energy waste as sound
  • thermal insulation - reduces heat loss
• unwanted energy transfers can be reduced by:

  • lubrication -reduces friction that produces heat
  • tightening loose parts - prevent unwanted vibrations so theres no energy waste as sound
  • thermal insulation - reduces heat loss
• specific heat capacity is the energy required to raise the temperature of 1kg of a substance by 1 degree