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Gravitational time dilation is a form of time dilation, an actual difference of elapsed time between two events, as measured by observers situated at varying distances from a gravitating mass. The lower the gravitational potential (the closer the clock is to the source of gravitation), the slower time passes, speeding up as the gravitational ...
Thermodynamic work is one of the principal kinds of process by which a thermodynamic system can interact with and transfer energy to its surroundings. This results in externally measurable macroscopic forces on the system's surroundings, which can cause mechanical work, to lift a weight, for example, [1] or cause changes in electromagnetic, [2] [3] [4] or gravitational [5] variables.
The equivalence between inertia and gravity cannot explain tidal effects – it cannot explain variations in the gravitational field. [10] For that, a theory is needed which describes the way that matter (such as the large mass of the Earth) affects the inertial environment around it.
Work started by Don Page and William Wootters [7] [8] [9] suggests that the universe appears to evolve for observers on the inside because of energy entanglement between an evolving system and a clock system, both within the universe. [10] In this way the overall system can remain timeless while parts experience time via entanglement.
In the second part, The World without Time, Rovelli writes that events constitute the universe instead of particles, and introduces the concept of quanta of time in loop quantum gravity. The final section, The Sources of Time, proposes that the apparent flow of time is due to the inability to observe all the microscopic details of the world. [4]
Gravity is usually measured in units of acceleration.In the SI system of units, the standard unit of acceleration is metres per second squared (m/s 2).Other units include the cgs gal (sometimes known as a galileo, in either case with symbol Gal), which equals 1 centimetre per second squared, and the g (g n), equal to 9.80665 m/s 2.
For two pairwise interacting point particles, the gravitational potential energy is the work that an outside agent must do in order to quasi-statically bring the masses together (which is therefore, exactly opposite the work done by the gravitational field on the masses): = = where is the displacement vector of the mass, is gravitational force acting on it and denotes scalar product.
Certain physical phenomena are highly sensitive to the value of the work function. The observed data from these effects can be fitted to simplified theoretical models, allowing one to extract a value of the work function. These phenomenologically extracted work functions may be slightly different from the thermodynamic definition given above.