What are the main forms of energy?
Energy
where 



E


{\displaystyle E}

 is the amount of energy transferred, 



W


{\displaystyle W}

 represents the work done on the system, and 



Q


{\displaystyle Q}

 represents the heat flow into the system. As a simplification, the heat term, 



Q


{\displaystyle Q}

, is sometimes ignored, especially when the thermal efficiency of the transfer is high.