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The gravitational potential energy is the potential energy an object has because it is within a gravitational field. The magnitude of the force between a point mass, M {\displaystyle M} , and another point mass, m {\displaystyle m} , is given by Newton's law of gravitation : [ 3 ] F = G M m r 2 {\displaystyle F={\frac {GMm}{r^{2}}}}
The time rate of heat flow into a region V is given by a time-dependent quantity q t (V). We assume q has a density Q, so that () = (,) Heat flow is a time-dependent vector function H(x) characterized as follows: the time rate of heat flowing through an infinitesimal surface element with area dS and with unit normal vector n is () ().
Internal energy: The energy contained within a body of matter or radiation, excluding the potential energy of the whole system, and excluding the kinetic energy of the system moving as a whole. Heat : Energy in transfer between a system and its surroundings by mechanisms other than thermodynamic work and transfer of matter.
In astrophysics, gravitational compression is a phenomenon in which gravity, acting on the mass of an object, compresses it, reducing its size and increasing the object's density. In the core of a star such as the Sun, gravitational pressure is balanced by the outward thermal pressure from fusion reactions, temporarily halting gravitational ...
L is the height of the container g is the acceleration due to gravity ν is the kinematic viscosity α is the thermal diffusivity β is the thermal expansion coefficient. As the Rayleigh number increases, the gravitational forces become more dominant. At a critical Rayleigh number of 1708, [5] instability sets in and convection cells appear.
The flow of heat is a form of energy transfer. Heat transfer is the natural process of moving energy to or from a system, other than by work or the transfer of matter. In a diathermal system, the internal energy can only be changed by the transfer of energy as heat: =.
Geopotential height differs from geometric height (as given by a tape measure) because Earth's gravity is not constant, varying markedly with altitude and latitude; thus, a 1-m geopotential height difference implies a different vertical distance in physical space: "the unit-mass must be lifted higher at the equator than at the pole, if the same ...
The macroscopic energy equation for infinitesimal volume used in heat transfer analysis is [6] = +, ˙, where q is heat flux vector, −ρc p (∂T/∂t) is temporal change of internal energy (ρ is density, c p is specific heat capacity at constant pressure, T is temperature and t is time), and ˙ is the energy conversion to and from thermal ...