Recent content by Sabian

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    [Kinetic Theory] Speed of diffusion.

    You are rigut, it's w^4 but the result of the integral is right anyway. So I should divide by the integral of dN_w^e over all speeds, which I think it is: \frac {\sigma N}{sqrt \pi V c^3} . \frac {c^4}{2} = \frac {\sigma N c}{2 \sqrt \pi V} The I have \frac { \frac {\sigma N } {\sqrt \pi...
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    [Kinetic Theory] Speed of diffusion.

    Homework Statement Find the mean speed of the molecules escaping through a hole of area \sigma. The vessel has volume V and the molecules mass m.Homework Equations dN_w^e = \frac {dA}{4V} w \frac{dN_w}{dw} dw w is the speed. dN_w = \frac {4N}{\sqrt \pi c^3} w^2 \exp {\frac {-w^2}{c^2} }dw...
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    [Doubt] Chemical Potential of an Ideal Gas

    Good catch on the molar dependance, hadn't looked at that. The excercise I was looking at says \mu (P,T,n) . I have some doubts on that being on purpose, but anyway... ------------------ Then I have G = n c_v T + U_0 - T \left (S_0 + n c_v ln (T) + nR ln \left ( \frac{RT}{P} \right ) \right...
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    [Doubt] Chemical Potential of an Ideal Gas

    Homework Statement Basically, find the chemical potential of an ideal gas knowing its heat capacities.Homework Equations P V = n R T \ \ \ \ (1) U = n c_V T + U_0 \ \ \ \ (2) S = S_0 + n c_V ln (T) + nR ln (V) = S_0 + n c_V ln (T) + nR ln \left ( \frac{nRT}{P} \right ) \ \ \ \ (3) \mu = \left...
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    [Thermodynamics] Two bodies exchanging heat through a Carnot engine

    You are right, I don't know why I try to make it so complicated. Just for the exercise to be complete if someone looks for this: - \frac {C_P dT_C}{C_P dT_H} = \frac {T_C}{T_C} \Longrightarrow \frac {dT_C}{T_C} = - \frac {dT_H}{T_H} Then integrating that condition through the whole process...
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    [Thermodynamics] Two bodies exchanging heat through a Carnot engine

    I'll start again to be more clear on the notation First law applied to the engine: \delta Q + \delta W_{on} = 0 \delta Q_H + \delta Q_C = - \delta W_{on} , where the work here is the on done ON the engine, so, changing for the work done BY it and considering absolute values of heat...
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    [Thermodynamics] Two bodies exchanging heat through a Carnot engine

    Thanks for such quick answers man. I'm quitting study now, it's beer time :P, but tomorrow I'll look into it and write what I get.
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    [Thermodynamics] Two bodies exchanging heat through a Carnot engine

    Thanks for your reply. Which information am I adding that way? The first law is already implied. I think I have to incorporate the fact that it's not an ordinary engine, but a Carnot one, which won't come up that way. I thought something like \frac {\delta W}{\delta Q_H} = \frac {|Q_H| -...
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    [Thermodynamics] Two bodies exchanging heat through a Carnot engine

    Homework Statement It's basically the classic problem I've seen here a lot. There are two bodies, both with equal heat capacity (C_P), one at temperature T_1 and the other at T_2. They exchange heat using an infinitesimal-reversible Carnot Engine, which will work until thermal equilibrium is...
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    Universe entropy variation of one body and a reservoir

    I could figure it out, thanks man, really.
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    Universe entropy variation of one body and a reservoir

    I know it's rude to bump threads, but does anybody have the time and knowledge to help me?
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    Universe entropy variation of one body and a reservoir

    Homework Statement One body of constant pressure heat capacity C_P at temperature T_i it's placed in contact with a thermal reservoir at a higher temperature Tf. Pressure is kept constant until the body achieves equilibrium with the reservoir. a) Show that the variation in the entropy of the...
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    Can a Physics Major Thrive in Earth Science Careers?

    I think it's a bit late to answer the original poster but I'll write how I ended up as an undergrad student of Geophysics myself. Luckily it's not a long story, in high school although I liked almost everything, the only things I would keep thinking out of the classroom where Maths...
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