# Tagged Questions

Covers the study of (mostly homogeneous) macroscopic systems from a heat/energy/entropy point of view. Maybe combine with [tag:statistical-mechanics].

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### finding change in internal energy for gas+thermodynamics problem [on hold]

So I'm given this problem, and for some reason when I solve for Q and delta U my answer is off, should be delta U = 249.3J and Q = 415.5J ...
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### Why the breath sometimes warm and sometimes cold? (2 different explanations!)

If you blow air against your hand with your mouth open, you feel warm breath. If you do with with your lips closed except for a small opening, you feel cold breath. One explanation from here says "...
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### Does the shape of a meteor make any difference during an impact?

Would the shape of the meteor make a difference on the impact? Like a Olympic diver would a spear shaped meteor make less damage to the surface of the Earth while creating more magma movement rather ...
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### Is there a maximum temperature? [duplicate]

I have read about absolute zero. I understand that it is impossible to cool a system below absolute zero (or to absolute zero for that matter). However, is there a maximum temperature? My intuition ...
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### Infer geophysical underground structure from thermal photography of the ground

Is it possible to determine (approximately of course) the geophysical structure of the underground under a certain region, using only a thermographic picture of the upper ground of the region ? The ...
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### What is the temperature of water at the end of the pipe?

I need to solve the following problem for a practical application. Water, initially at temperature $T_0$, flows with a constant speed $v$ through a PVC tube of length $l$ and diameter $D$. The ...
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### What is entropy really?

On this site, change in entropy is defined as the amount of energy dispersed divided by the absolute temperature. But I want to know: What is the definition of entropy? Here, entropy is defined as ...
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### What causes a heat generating source to stabilize at a certain temperature? (Answered by myself, I think)

For example, we out a heat sink on a microprocessor to keep it cooler. I understand that if we run 100 watts of electricity through the microprocessor, it will generate 100 watts of heat, or 100 ...
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### Thermodynamics, chaperones : How to model polymer fragmentation

Living polymers are well described by equilibrium statistical physics. Now I would like to consider a case were living polymers undergo fragmentation due to chaperones. I can think of a kinetic ...
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### Why does a soda bottle foam or froth when dropped? [duplicate]

Secondly, if I do drop a soda bottle how long do I have to keep it for it to return to its original state or condition, I.e. safe to open without froth spraying everywhere; or is there some rule of ...
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### Proving that the Boltzmann entropy is equal to the thermodynamic entropy

I've been trying to understand how we can equate the Boltzmann entropy $k_B \ln \Omega$ and the entropy from thermodynamics. I'm following the approach found in the first chapter in Pathria's ...
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### How do the human heat sensors work?

I have been wondering about this particular issue for quite some time now. It feels like I should know this as a master's student in physics. The questions are, essentially, the following: What is ...
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### Thermodynamics : Work done on gas inside container by the force due to pressure exerted by external atmosphere

Suppose a container is fitted with a massless and frictionless piston lying on a table such that pressure due to gas is greater than pressure due to external atmosphere. Hence piston will move. Now ...
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### Please explain entropy curve [closed]

I saw this curve at a website, but I didn't understand it. What is the lower point of entropy, and what are the points A, B, and C? Thanks!
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### Will heat flow by conduction oscillate until thermodynamic equilibrium is reached in a solid object?

Consider the following thought experiment with $2$ conducting objects $A$ and $B$, where object $A$ is initially at a much higher temperature than object $B$. The objects are now placed in perfect ...
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### energy efficiency - dryer vs hang+dehumidifer

When I have wet clothes coming out of the washing machine, I can either tumble-dry them in an electric clothes-dryer, or I can hang them to dry. But I can only hang them in a basement. The basement ...
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### Mathematical method of Physics [closed]

Please any one can tell me how to get lecture of mathematical method of physics complete course online download complete lecture series. Which professor best for this subject please guide me how to ...
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### Why don't the less denser steam move up, leaving the more denser water drop to fall on hot pan in Leidenfrost effect?

In Leidenfrost effect, the hot steam suspends water droplets above it and prevent the drop from touching the hot pan. My question is, as the steam is less denser than water, should the steam not ...