Action (physics)In physics, action is a scalar quantity describing how a physical system has changed over time (its dynamics). Action is significant because the equations of motion of the system can be derived through the principle of stationary action. In the simple case of a single particle moving with a constant velocity (uniform linear motion), the action is the momentum of the particle times the distance it moves, added up along its path; equivalently, action is twice the particle's kinetic energy times the duration for which it has that amount of energy.
Stationary-action principleThe stationary-action principle – also known as the principle of least action – is a variational principle that, when applied to the action of a mechanical system, yields the equations of motion for that system. The principle states that the trajectories (i.e. the solutions of the equations of motion) are stationary points of the system's action functional. The principle can be used to derive Newtonian, Lagrangian and Hamiltonian equations of motion, and even general relativity, as well as classical electrodynamics and quantum field theory.
Aja peopleThe Aja also spelled Adja are an ethnic group native to south-western Benin and south-eastern Togo. According to oral tradition, the Aja migrated to southern Benin in the 12th or 13th century from Tado on the Mono River, and 1600, three brothers, Kokpon, Do-Aklin, and Te-Agbanlin, split the ruling of the region then occupied by the Aja amongst themselves: Kokpon took the capital city of Great Ardra, reigning over the Allada kingdom; Do-Aklin founded Abomey, which would become capital of the Kingdom of Dahomey; and Te-Agbanlin founded Little Ardra, also known as Ajatche, later called Porto Novo (literally, "New Port") by Portuguese traders and the current capital city of Benin.
Gbe languagesThe Gbe languages (pronounced ɡ͡bè) form a cluster of about twenty related languages stretching across the area between eastern Ghana and western Nigeria. The total number of speakers of Gbe languages is between four and eight million. The most widely spoken Gbe language is Ewe (10.3 million speakers in Ghana and Togo), followed by Fon (5 million, mainly in Benin). The Gbe languages were traditionally placed in the Kwa branch of the Niger–Congo languages, but more recently have been classified as Volta–Niger languages.
