Energy It is equal to the energy expended (or work done) in applying a force of one newton through a distance of one metre. However energy is also expressed in many other units not part of the SI, such as ergs, calories, British Thermal Units, kilowatt-hours and kilocalories, which require a conversion factor when expressed in SI units. The SI unit of energy rate (energy per unit time) is the watt, which is a joule per second. Thus, one joule is one watt-second, and 3600 joules equal one watt-hour. The CGS energy unit is the erg and the imperial and US
History of UNIT alien threats, and Sarah Jane is concerned that UNIT would treat her son Luke as a test subject with no regard for his human rights should they discover him. UNIT returned in the 2009 Easter special "Planet of the Dead" investigating the disappearance of the 200 bus. Captain Erisa Magambo makes a reappearance from her last in "Turn Left" as the commander of UNIT, aided by the new scientific adviser Malcolm Taylor. They appeared again during "Death of the Doctor" which introduced a UNIT Base at Mount Snowdon. In 2012, after a 3-year absence, UNIT returned to "Doctor Who" in