please give me a solution

i need to find the value of V in the following equation

(p+(a/V^2))*(V-b)=RT

where

P=9500KPa

R=.2968Kj/k/kg

T=175 K

a=27R^2*Tcr^2?(64*Pcr)

b=(R*Tcr)/(8Pcr)

Tcr=136.2 K

Pcr=3.39MPa

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- Apr 27th 2009, 11:35 AMself_shatteredSubstituting values and solving for an unknown
please give me a solution

i need to find the value of V in the following equation

(p+(a/V^2))*(V-b)=RT

where

P=9500KPa

R=.2968Kj/k/kg

T=175 K

a=27R^2*Tcr^2?(64*Pcr)

b=(R*Tcr)/(8Pcr)

Tcr=136.2 K

Pcr=3.39MPa - Apr 27th 2009, 11:09 PMGrandadNumerical solution of equations
Hello self_shattered$\displaystyle (p+(a/V^2))(V-b)=RT$

$\displaystyle \Rightarrow (pV^2+a)(V-b)=RTV^2$

$\displaystyle \Rightarrow pV^3-(b+RT)V^2+aV-ab=0$

The best advice I can give now is to use a numerical method; e.g. Newton-Raphson, with $\displaystyle f(V)= pV^3-(b+RT)V^2+aV-ab$ and $\displaystyle f'(V) = 3pV^2-2(b+RT)V+a$.

I'm not sure what the numerical values are, especially

Quote:

a=27R^2*Tcr^2?(64*Pcr)

If you don't know how to use Newton-Raphson, work out the numerical values of $\displaystyle p, a, b, R, T$ (don't bother with the units, they only confuse things); post them here, and I'll do it for you.

Grandad