A constant-pressure piston/cylinder assembly contains 0.2 kg of water as saturated vapor at 400 kPa. It is now cooled so that the water occupies half of the original volume. Find the work and heat transfer for the process.

W= -18.489 kJ

Q= -213.4 kJ

Explanation:

We are given following data for water:  

From "Saturated Water Pressure Entry" table  corresponding to pressure

P = 400kPa we can obtain specific volume and internal energy:  

We can calculate final specific volume from given data in problem:

Work done for constant pressure process is:  

Find specific internal energy is given by:  

We must calculate first dryness fraction:

Specific internal energy is:

Heat transfer is given by:

russian is not my first language, so i'm afraid i can't write out an answer in russian, but hopefully you can find a way to do so. here's my best translation of the problem: you're given a plot of a particle's position in one-dimensional space over time, and you're asked to find either the total distance traveled by the particle after 6 seconds had elapsed, or the total displacement of the particle after 6 seconds.

if you want the total distance traveled, you would first need to determine the particle's velocity as a function of time, then integrate that over the 6-second interval. we know the position function is quadratic with roots at 0 and 6, so we have

where is unknown. because the position is parabolic, there is symmetry about the midpoint at , and we know that

so that the position function is

which means the velocity is

then the total distance traveled is

so the total distance traveled is 20 m.

on the other hand, if you want to find displacement: the particle starts at and ends at , so its displacement is 0.