Homework Help: Fundamental thermo systems problem

1. Jan 31, 2014

kik369

1. Unit mass of a fluid at a pressure of 3 bar, and with a specific volume of 0.18 m3/kg, contained in a cylinder behind a piston expands reversibly to a pressure of 0.6 bar according to the law p = c/v2, where c is a constant. Calculate the work done during the process.

2. P1V1=P2V2

3. I know that the answer is 29.82 J/kg out of the system, but how to get it?

2. Jan 31, 2014

RTW69

c=p1*v12 but work=∫p*dv=∫c/v2*dv=c∫dv/v2 the rest is basic calculus. The answer units should be kj/kg

3. Jan 31, 2014

RTW69

c=Subscript[p, 1]*Subsuperscript[v, 1, 2] but work = \[Integral]p \[DifferentialD]v =\[Integral]c/v^2 \[DifferentialD]v = c \[Integral]1/v^2 \[DifferentialD]v the rest is basic calc. I believe the answer units is KJ/Kg

4. Jan 31, 2014

RTW69

Guess I can't copy mathematica text into the message box

5. Jan 31, 2014

kik369

Thank you! I'll go through this tomorrow. I've been working on these problems the whole day. It is time for me to take a break. I appreciate the reply.