Chapter 24, Problem 48A

Carlos says that perpetual motion machines are impossible to construct. John says that perpetual motion is common in nature—the motion of molecules, for example. Do you agree with Carlos, John, or both?

To determine

To explain: The statement given by person C or person J or both is correct.

Explanation of Solution

Introduction:

Perpetual motion is defined as the motion of bodies that will continue forever. A perpetual motion machine is a machine which can do infinite work without any input energy source. It is a hypothetical machine.

A perpetual motion machine of first kind will produce work without any input source. Thus, violating the first law of thermodynamics (law of conservation of energy). Machine of second kind will spontaneously converts the thermal energy into mechanical work. So, if thermal energy is equivalent to the work done then this will not violate the first law of thermodynamics but it violates the second law of thermodynamics. Machine of third kind is one that eliminates friction along with dissipative forces completely in order to maintain motion forever. But this is impossible to construct as dissipation can never be completely eliminated.

According to person C, the perpetual machines are impossible to construct and that is true.

According to person J, perpetual motion is common in nature and this is also true because this machine continues its motion forever with no reduction in speed that is the motion of molecules.

Conclusion:

Hence, the statement given by person J and person C are correct.