 an erg (short for ergon, a greek word meaning "work/task"oxford english dictionary) is a unit of energy and mechanical work equal to 10â7 joules. it originated in the centimetreâgramâsecond (cgs) system of units, symbol "erg". it is not an si unit. an erg is the amount of work done by a force of one dyne exerted for a distance of one centimeter. in the cgs base units, it is equal to one gram centimeter-squared per second-squared (gÂ·cm2/s2). it is thus equal to 10â7 joules or 100 nanojoules (nj) in si units. an erg is approximately the amount of work done (or energy consumed) by one common house fly performing one "push up", the leg-bending dip that brings its mouth to the surface on which it stands and back up.filippenko, alex, understanding the universe (of the great courses, on dvd), lecture 44, time 24:30, the teaching company, chantilly, va, usa, 2007 1 erg = 10â7 j = 100 nj 1 erg = 10â10snÂ·m = 100 psnÂ·m = 100 picosthÃ¨ne-metres 1 erg = 624.15 gev =  1 erg = 1 dyne cm = 1 gÂ·cm2/s2 ==history== in 1864, rudolf clausius proposed the greek word () ergon for the unit of energy, work and heat.  in 1873, a committee of the british association for the advancement of science, including british physicists james clerk maxwell and william thomson defined the c.g.s. system of units, and recommended the name erg or ergon for the c.g.s. unit of energy.{{cite conference |url= http://www.biodiversitylibrary.org/item/94452#page/324/mode/1up |title=first report of the committee for the selection and nomenclature of dynamical and electrical units |date=september 1873 |conference= forty-third meeting of the british association for t
Centimetreagramasecond_system_of_units Units_of_energy