Summary of Important Quantities, Equations and Concepts

Table 7.1: Summary of the symbols and units of the quantities used in Energy

Units
Quantity	Symbol	Unit	S.I. Units		Direction
Work	W	J	N.m	or${\displaystyle kg.m^{2}.s^{-2}}$	--
Kinetic Energy	EK	J	N.m	or${\displaystyle kg.m^{2}.s^{-2}}$	--
Potential Energy	EP	J	N.m	or${\displaystyle kg.m^{2}.s^{-2}}$	--
Mechanical Energy	U	J	N.m	or${\displaystyle kg.m^{2}.s^{-2}}$	--

Principle of Conservation of Energy: Energy is never created nor destroyed, but merely transformed from one form to another.

Conservation of Mechanical Energy: In the absence of friction, the total mechanical energy of an object is conserved.