Written by Jerry Ratzlaff. Posted in Electromagnetics

Energy is never created or destroyed First Law of Thermodynamics, but it can be transferred from one object to another.  It also comes in many different forms (kinetic, potential, thermal, chemical, electrodynamic and nuclear) and can be converted from any one of these forms into any other, and vice versa.  Energy can be converted from one form to another in three basic ways: through the action of forces (gravitational forces, electric and magnetic force fields, frictional forces), when atoms absorb or emit photons of light and when nuclear reaction occurs.

Typical units for mechanical energy is foot-pounds and joules, english energy is British thermal unit. \(\;Btu = \frac {ft-lbf}{J}\)


\( E = m   U \;\)

\( E = F l =  \frac {ml^2}{t^2}  \) 


\(E\) = energy

\(m\) = mass

\(U\) = internal energy

\(F\) = force

\(l\) = length

\(t\) = time