Energiakifejezés

Energiakifejezés is a term used in physics and engineering to refer to the mathematical expressions that quantify energy in a system. It encompasses the various forms of energy—such as kinetic, potential, internal (thermal), and electrical energy—and serves as a compact representation of how energy is stored, transformed or transferred. The concept is central to analyses of physical processes, engineering design, and thermodynamic accounting.

Common forms and examples of energiakifejezések include the following. Kinetic energy is expressed as E_k = 1/2 m v^2, where m is mass and v is velocity. Gravitational potential energy near the Earth is E_p = m g h, with g the acceleration due to gravity and h height. Electrical energy stored in a capacitor and inductor can be written as E_C = 1/2 C V^2 and E_L = 1/2 L I^2, respectively. Internal or thermal energy is represented by U, which depends on state variables such as temperature and volume; in thermodynamics its change is governed by ΔU = Q − W, where Q is heat and W is work. In many mechanical systems, the total energy E = E_k + E_p remains constant under conservative forces. In analytical mechanics, the Lagrangian L = T − V and the Hamiltonian H = T + V formalize energy concepts for a wide range of systems.

Significance and usage follow from the conservation of energy: energiakifejezés provide the means to calculate work, efficiency, and energy transfer, and to formulate objective criteria in design and analysis. The term reflects a standard educational and technical layer in Hungarian-language physics, engineering, and applied sciences, where energy representations are used to model and reason about physical phenomena.