# Example 4.1  
 P1   =   200 kPa
 V1   =   0.04 m^3 
 V2   =   0.10 m^3 
 W12 = P1  * (V2 - V1) ; kJ
 W12 = P1   * V1 * ln(V2 / V1) ; kJ 
 n   =   1.30 
 P2 = P1  * (V1 / V2)^n ; kPa 
 W12 = (P2  * V2 - P1  * V1) / (1 - n) ; kJ 


# Example 4.2     
 mp   =   1 kg
 A0  =   1 m^2
 P0   =   1.00 kPa
 ks   =   1.00 N/m
 x_minus_x0   =   1.00 m
 F1   =   1.00 N
 P = P0 + (mp * grav() + F1 + ks * x_minus_x0) / A0 ; kPa 


# Example 4.3       
 m0  =   0.50 kg
 T1   =   -20 degC
 x1   =   0.25 
 T2   =   20.00 degC
 V2_over_V1   =   1.41 
 Psat   =   190.20 kPa
 P1 = Psat
 nf  =   0.001504 m^3/kg
 nfg  =   0.62184 m^3/kg
 n1 = nf + x1 * nfg  ; m^3/kg 
 n2 = V2_over_V1 *  n1   ; m^3/kg 
 P2    =   600.00 kPa
 W12 = (1/2)  * m0 * (P1 + P2) *  (n2 - n1) ; kJ 


# Example 4.4       
 m0  =   0.10 kg
 P1   =   1000 kPa
 T1   =   500 degC
 V2_over_V1   =   0.50 
 n1  =   0.35411 m^3/kg
 n2 = V2_over_V1 *  n1   
 Psat   =   3.169 kPa
 P2 = Psat
 W12 = m0  * P1  * (n2 - n1)  ; kJ 

# Example 4.5      
 mp   =   1 kg
 P1   =   1 Mpa
 V1   =   1 m^3
 Pext   =   1 Mpa
 V2   =   0.5 m^3
 W12 = Pext  * (V2 - V1)  ; kJ 


# Example 4.6      
 L0   =   1 m
 A0  =   1 m^2
 E  =   1 Mpa
 e  =   0.010 
 F0 = A0  * E  * e ; N 
 W12 = -(1/2)  * A0  * E  * L0  * e^2  ; kJ 


# Example 4.7      
 Troom   =   20 degC
 Tambient   =   -10 degC
 Touter_glass   =   12.1 degC
 Dx  =   5 mm
 A0  =   0.5 m^2
 k  =   1.400 W/ m degK
 h  =   100.000 W/m^2 degK
 Qdotglass = -k  * A0  * (Troom - Touter_glass) / Dx  ; W 
 Qdotoutside = h  * A0  * (Touter_glass - Tambient) ; W 


# Homework Problems:

TBD