Work in thermodynamics

[est120]

i can't manage to grasp the concept of PV work in thermodynamics, for example we all know that W= integral(F*dx) like here

but this says that, at the end, W doesn't really depend on the gas temperature or reversible process crap
at the end W is simply a constant, atmospheric pressure is constant, piston weight is constant (and since V2=V1=0, and we neglect friction)
so that's absolutely understandable for me but in thermodynamics books:

and this doesn't agree with the first equation because here we need to have a reversible process in such a way that we can always associate a definite value for P to the gas
there is absolutely NO book that explains PV work in an understandable way , in thermodynamics, work isn't just "Force x distance"

 

[goutam_freelance]

The first part is a constant pressure process since pressure is constant. So W= P_integral(dV)=PA(z2-z1).
In second part both P and V are variable. So you need equation of state to define one variable in terms of the other. You can define states by equation of state only when the states are in thermodynamic equilibrium (or the process is reversible , quasi static i.e infinitely slow).

Engineers, think what we have done to the environment !

https://www.linkedin.com/in/goutam-das-59743b30/