Thermal dynamics Definition and 29 Threads

reference；sol The maximum reversible work in thermodynamics Below is the process of determining the "Available energy" for an open system, shared with everyone as a reference for learning about exergy. If there are any errors in the content, please feel free to correct them. $$...

Q： The maximum reversible work, self-solved, is as follows: Only when equation (5) equals zero will it match the textbook solution; kindly indicate any errors in the self-solution. reference. : sol.; exergy balance; CMS.; wrev. Q： The maximum reversible work, self-solved, is as follows: Only...

Hi, I am trying to build a product where i am placing a solar panel along with a driver board inside a Polycarbonate housing and closing it with a ABS cover at the back. The driver board is soldered at the back of the solar panel and placed inside the PC box. Then a RTV(silicone sealant for leds...

Q1: Why can't set ##Q_{in,net}=0## and use equation (2) to obtain ##W_{act,in}=\left( \bigtriangleup U \right) _{cv}##? Q2: If assume it's a reversible process, why can't equation (3) determine (△S)sys=0? ref1. ref2. $$ W_{rev,in}=W_{act,in}-W_{surr}=W_{act,in}+P_0\left( V_2-V_1 \right) \cdots...

I am a high school student and recently I have been working on a project about how temperature affects the frequency of a string emits. I have read blogs like https://www.physicsforums.com/threads/tension-and-frequency-with-change-in-temperature.833185/ and completed the part of thermal...

***A Carnot Engine*** is a theoretical engine unlike a Sterling Engine which can be made practically. Some of the drawbacks of Carnot Engine are, 1)The Heat Transfer occurs only during isothermal process(compression and expansion),this is because the working material (ie) gas or fuel used, if...

This is a fluid dynamic simulation. The top area has 100 degrees Celsius. The bottom area has 0 degrees Celsius. And both are filled with an ideal gas which is 1-atmosphere pressure. Two areas are connected through the left small line. Another part is blocked. So heat transfer can only happen...

This probe is designed to fly closer than 4 million miles from the sun's 'surface'. Is it possible in principle to cool the spacecraft 's inner facing surface by transferring heat to a cooler part and then radiating it into space from the far surface? I don't think it is equipped with such tech...

Hello. My name is Jon rotsler I'm an avid independent researcher when I have the time. I have a huge interest in quantum mechanics I'm also bid on thurmo dynamics and magnetic. But rarely have time to do all the fun things I would like so I'm settling for good discussion and a bouncing around of...

I've recently been reading a bit into the thermalisation of a system of particles and I'm unsure on a couple of concepts. Firstly, if a system of particles are out of mutual thermal equilibrium, does this essentially correspond to the particles in the system having randomly distributed momenta...

Homework Statement A cylindrical glass tube (linear thermal expansion coefficient ##\alpha##) contains liquid (volume thermal expansion coefficient ##\beta##). The height of the tube is ##h_{t,0}## and the height of the liquid inside of it is ##h_{l,0}##. If the temperature changes of an amount...

Homework Statement Freezing of water at 273 K and 1 atm which of the following is true for the above thermodynamics process p) q=0 q)w=0 r)ΔSsys<0 s)ΔU=0 t)ΔG=0 Homework Equations none[/B]The Attempt at a Solution [/B] i got r, s ,t since the reaction happens at constant...

Homework Statement This is more of a question that doesn't require formulas as much as common sense. The question goes,"If you have a ring that is heated up, would the hole in the middle get smaller or larger." Homework Equations N/A The Attempt at a Solution I know that when objects are...

Homework Statement I want to find the mathematical proof to show that the density of an object changes with thermal expansion. My professor showed this in class and it was horribly wrong because he let a few things out. The book I'm reading showed it in 4 steps and left out a lot of the crucial...

It is well known that the ideal gas law applies only to an ideal gas, one consisting of particles infinitesimal in size and exhibits no interactions between the particles. Considering an ideal gas, is the ideal gas law valid under non-equilibrium conditions? For example, does the ideal gas law...

Hey! I am trying to figure out this one problem. Some help would be appreciated. How can i relate the maximum distance traveled by an electron at a given pressure? So electron is colliding with air molecules. I wonder if there is a formula or derivation which relate maximum penetration and...

Homework Statement A warm water bath containing 10.0L of water is connected to an ice-water bath with a piece of metal of length L = 2.11 m and cross sectional area A = 1975 cm2. The metal has a thermal conductivity of km = 60.5 Wm-1K-1, a specific heat of cm = 239.7 Jkg-1K-1 and a density of...

A uniform rod of a length of 2.0 m at 5ºC has a coefficient of linear expansion of 5.0 × 10^-4 K^-1. How much longer is it when the temperature is 35ºC? I want to know the procedure to solve this problem This isn't hw, but I'm wondering how to solve it when it's K ^-1 Just trying to get some...

I am having trouble calculating the work done by a product gas in reversible adiabatic expansion, and in calculating the final temperature. pV gamma = constant, Cv = constant (assume), gamma = cv + nR / Cv. anyone who can help me out?

Hi Guys I have a relatively simple question (I think!), I am trying to calculate the amount of time it takes for a fridge to cool 1m3 of air from 20°C to 3°C while running a fridge's compressor at 200 watts I have calculated this using T = E/P From this I am trying to work out the time...

The information I am given is : a door has two steel layers both are .47 mm thick, the door itself is 725 mm by 1800mm. The question asks, how thick of a layer of wood (oak) would have to be put in the door to limit the heat loss to 740kJ per hour? Temp inside is 18C and outside is -20C All...

I have some car engine related questions, but basically just physics. -Do different specific heat capacities have anything to do with how certain materials resist heat? I know that on some engine compartments there is gold wrapping because it resists heat best, but it has a low specific...

WCFSGS' Version: Generalized Second Law of Thermodynamics We have known that there has been some generalization to the second law of thermodynamics. We like to present here the Version of WCFSGS about this generalization. At this moment, we are not quite sure if our version is different from...

Homework Statement Thermal Dynamics question, gases? So I have this box with lengths 20cm on each side. There are 100 balls inside of it with diameter 5mm each. The density in the box is 7.8 g/cm3. The bottom of the box vibrates so the balls bounce around. The top of the box has a movable...

Homework Statement A glass flask whose volume is 1000cm^{3} at a temperature of 0.00*10^0 Celsius is completely filled with mercury at the same temperature. When the flask and mercury are warmed together to a temperature of 52 Celsius, a volume of 8.35cm^{3} of mercury overflows the flask...

Homework Statement A flask with a volume of 2.70 L, provided with a stopcock, contains ethane gas (C_2 H_6) at a temperature of 297 K and atmospheric pressure 1.01×10^5 Pa. The molar mass of ethane is 30.1 g/mol. The system is warmed to a temperature of 396 K, with the stopcock open to the...

Homework Statement Q = ? ΔU = + 8.0x10^3 W = perhaps 0 since isovolumetric? Energy Lost = -2.0x10^3 Mass of Water = 2.0 kg Homework Equations I'm stuck on this thermal dynamics problem. It states: "A 2.0 kg quantity of water is held at constant volume in a puressure cooker and...

A 330-g glass mug at 16C is filled with 275 milliliters of water at 91C. Assuming no losses to the external environment, what is the final temperature of the mug? Im having a bit of trouble with this problem. Since we're assuming no losses, delta q=0. So, delta q= delta q(mug) + delta q...

So we had a "quick quiz" a while back and I forgot about it and completely bombed it. I understand everything I did wrong now except for one part... Here's the question: Originally I just used: ...that wasn't taking into account the time it takes to go "tick-tock" and I'm pretty sure it...