Perpetual motion, first kind

Consequence of First Law It is impossible to construct a machine ( perpetual motion machine of the first kind ) that produces useful work in a cyclic process without a compensating change in the surroundings. 

Are any of the following devices perpetual motion machines of the first or second kinds Which kind are they and why ... 

It is impossible to do work without expending an equivalent amount of energy or Perpetual motion of first kind is impossible . 

Even in its original form the theorem deals with chemical reactions and changes of state, that is to say, with the most important natural phenomena accompanied by evolution or absorption of heat. It is therefore natural to suspect that the heat theorem, like the two law s of thermodynamics, has its origin in the nature of heat itself. The laws of thermodynamics, as was shown in Chapters III. and V., could be traced back to the results of our everyday experience (impossibility of perpetual motion of the first and second kinds). This simple method of derivation fails in the case of the new theorem because temperatures in the neighbourhood of the absolute zero can never be the immediate objects of experience. They can only be reached by refined experimental methods. For this reason Nernst s theorem can never be susceptible of direct experimental proof, and can only be tested by its consequences. We can deduce the theorem, however, from a more general principle regarding the nature of heat and the properties of the thermodynamic functions. 

This law is movitated by the fact that perpetual motion of the first kind is not possible, i.e. no work without consuming fuel. The first law can be written in the differential form... 

Following historical precedent, the validity of the first law of thermodynamics has here been associated with the impossibility of perpetual motion of the first kind and the constancy of the mechanical equivalent. The law has nevertheless a much firmer basis, for it leads to a wide variety of conclusions, as will be seen in this and later chapters, which have been found to be in complete agreement with actual experience. 

This equation is an expression of the impossibility of perpetual motion of the first kind, as stated in 6c. Provided the system does not undergo any net change, i.e., AE is zero, it is impossible to produce work without drawing upon energy, namely heat, from an outside source. A process or series of processes as a result of which the system returns exactly to its original thermodynamic state is referred to as a cyclic process or cycle. In any cycle AE is zero, and the heat absorbed Q is equal to W the work done by the system, in accordance with equation (7.3). 

A consequence of the impossibility of converting heat isothermally into work in a continuous manner is the impracticability of what is called perpetual motion of the second kind/ that is, the utilization of the vast stores of energy in the ocean and in the earth. There is nothing contrary to the first law of thermodynamics in this concept, but the fact that it has not been found feasible provides support for the second law. The ocean, for example, may be regarded as a heat reservoir of constant temperature, and the law states that it is not possible to convert the heat continuously into work without producing changes elsewhere. 

Q. 10.3 An inventor sends a patent application to the Patent office. In it (s)he claims to have found a chemical compound ensures eternal youth for all who drink it. The patent office rejects it on the basis that the formulation is a perpetual motion machine. Explain why. Did they reject it because it was a perpetual motion machine of the first or second kind ... 

This is a perpetual motion machine of the first kind and violates the first law of thermodynamics. The transfers of energy that occur in this machine will never be able to overcome the frictional losses that are inevitable. The machine will run down. Even if it were possible to make it completely loss-less, it would never be able to produce more energy than was put into it and so at best it would be a curiosity and not a useful or practical machine. Alas even the case of 100% efficiency is impossible. 

Energy is conserved in all transformations. A perpetual motion machine of the first kind is a machine that by its action creates energy by some transformation of a system. The first law of thermodynamics asserts that it is impossible to construct such a machine not that people have not tried No one has ever succeeded, but there have been some famous frauds in this field. 

The second law in this form denies the possibility of what has sometimes been called perpetual motion of the second kind, just as the first law denies that of the first kind, which is generation of work from nothing at all. 

Laws may be also presented as classical statements about the impossibility of the perpetual motion of the first and second kind. 

Perpetual motion of the third kind. A form of motion that continues indefinitely but without doing any useful work. An example is the random molecular motion in a substance. This type postulates the complete elimination of friction. A mechanism consisting of frictionless bearings maintained in a vacuum could turn indefinitely, once started, without contravening the first or second laws of thermodynamics, provided it did no external work. Experience indicates that on the macroscopic scale such a condition cannot be achieved. On the microscopic scale, however, a superconducting ring of wire will apparently sustain a perpetual current flow without the application of an external force. This could be considered a form of... 

It is easy to see the equivalence of this statement to the above formulation summarized in equation (2.2.1). And note how this statement is entirely in macroscopic, operational terms it has no reference whatsoever to the microscopic structure of matter. The process described above is called perpetual motion of the first kind. 

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