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The work done is given by the dot product of the two vectors, where the result is a scalar. When the force F is constant and the angle θ between the force and the displacement s is also constant, then the work done is given by: = If the force is variable, then work is given by the line integral:
Work done by force fields can be done indefinitely slowly, so as to approach the fictive reversible quasi-static ideal, in which entropy is not created in the system by the process. In thermodynamics, non-mechanical work is to be contrasted with mechanical work that is done by forces in immediate contact between the system and its surroundings.
Any work (δW) done must be done at the expense of internal energy U, since no heat δQ is being supplied from the surroundings. Pressure–volume work δW done by the system is defined as δ W = P d V . {\displaystyle \delta W=P\,dV.}
This article uses the physics sign convention for work, where positive work is work done by the system. Using this convention, by the first law of thermodynamics, The yellow area represents the work done = + where W is work, U is internal energy, and Q is heat. [1] Pressure-volume work by the closed system is defined as:
The central concept of thermodynamics is that of energy, the ability to do work. By the First Law , the total energy of a system and its surroundings is conserved. Energy may be transferred into a system by heating, compression, or addition of matter, and extracted from a system by cooling, expansion, or extraction of matter.
In these cases, the above three conditions are not mathematically equivalent. For example, the magnetic force satisfies condition 2 (since the work done by a magnetic field on a charged particle is always zero), but does not satisfy condition 3, and condition 1 is not even defined (the force is not a vector field, so one cannot evaluate its curl).
The value of work done (VOWD) is a project management technique for measuring and estimating the project cost at a point in time. It is mainly used in project environments of the Petroleum industry and is defined as the value of goods and services progressed, regardless of whether or not they have been paid for or received.
Work (physics), the product of force and displacement Work (electric field), the work done on a charged particle by an electric field; Work (thermodynamics), energy transferred by the system to its surroundings; Creative work, a manifestation of creative effort Work of art, an artistic creation of aesthetic value; Career, an individual's ...