Thermodynamics: Work, True/False Questions

[CVB]

Hello, I have some questions to say true or false.
a) In a P,T,V system always will be true $$\int P dv \geq W_{out}$$ if the system has friction.
b)In Thermodynamic the work who cross system border is always process function
c)The adiabatic work in Thermodynamic who cross the border in a closed system is independent of process and depends of the final and initial status
d)In a Expansion no reverse it`s true $$W_{expansion}=W_{useful}+\left|W_{friction}\right|+W_{atmospheric}$$

The Attempt at a Solution

Well I think a) and c) are true and b) d) are false

Thank you

 

[mark726]

for your post and your questions. I can confirm that your answers are correct. Let me explain why.

a) In a P,T,V system, the work done by the system is given by the integral of pressure (P) with respect to volume (V). This is known as the mechanical work, and it represents the energy that is transferred from the system to its surroundings. If the system has friction, some of this work will be lost due to the conversion of mechanical energy into heat. Therefore, the integral of P with respect to V will always be greater than or equal to the work done by the system in the presence of friction.

b) In thermodynamics, a process function is a property that only depends on the initial and final states of the system, and not on the path taken to get there. Work is an example of a process function, as it only depends on the initial and final states of the system, regardless of the path taken to get there. Therefore, the work done by a system is always a process function.

c) The adiabatic work done by a closed system is independent of the process because it does not exchange heat with its surroundings. This means that the work done is solely determined by the initial and final states of the system, and not by the path taken to get there. Therefore, it is a process function.

d) In an expansion, the work done by the system is equal to the useful work (the work that is used to do something) plus the work done against friction (the work that is lost due to friction) plus the work done against atmospheric pressure (the work that is done to push against the surrounding air). Therefore, the statement that W_{expansion}=W_{useful}+\left|W_{friction}\right|+W_{atmospheric} is true.