Other units of energy In cgs units, one erg is 1&nbsp; g &nbsp; cm 2 &nbsp; s &minus;2 , equal to 1.0&times;10 &minus;7 &nbsp;J. The imperial / U.S. units for both energy and work include the foot-pound force (1.3558&nbsp;J), the British thermal unit (Btu) which has various values in the region