Thermal Definition and 1000 Threads

A quartz tube contains one mom of gAs at 20 deg c. The gas is heated at constant volume to 300 deg c. How much thermal energy is transferred to the gas? If the same amount were heated at constant pressure, how muh energy would be required? I know how to solve this for constant volume using E=...

Homework Statement You have been assigned to design brass pistons to slide inside steel cylinders. The engines in which these pistons will be used will operate between 20.0 degrees Celsius and 150.0 degrees Celsius. Assume that the coefficients of expansion are constant over this temperature...

Dear Experts Does anyone know how big can we extend the gap between the 2 plates? Thanks. Regards Ramone

Homework Statement If you were to shake bottle with some water in it for about ten minutes, then roughly, how much would the temperature increase? Homework Equations K=1/2mv^2 U=N*f*1/2*k*T The Attempt at a Solution I think we need to find kinetic energy and assume it all gets...

Homework Statement Suppose a cup of boiling water (m=250g) instantaneously cools to room temperature (25°C) with the liberated thermal energy going into translational KE. How fast will the cup fly off the table? Assume the water molecules have 18 degrees of freedom. Homework Equations...

Okay, so firstly sorry if this is a poor post/wrong topic, I'm kind of new here, and it's been a while! I'm given an example of a quasistatic process, in a frictionless piston. The piston compresses an ideal gas from Vi to Vf, and pressure increases from Pi to Pf, all at a constant temperature...

I want to propose an interesting thought experiment, but don't want to A/ make a bigger fool of myself than I normally do B/ well that's about it really The premise behind my experiment is that rising steam does not lose thermal energy if we ignore thermal losses both radiative and conductive...

Hey All, Have any of you ever worked with thermal software such as Flixo and Therm? I'm having a problem with U-Value calculations differing between the two programs, and I would really liek to get to the bottom of why. What I'm thinking: I am coming up with some ideas based on some...

I have a bearing that is fixed into its housing by means of an interference fit (to test the effects of having a bearing that has become stuck due to build up of contaminants). I am using a bearing of ID 15.92mm ± 0.005 made of High lead Tin Bronze Alloy with a thermal coefficient of expansion...

A brass ring of diameter 10.00 cm at 19.9°C is heated and slipped over an aluminum rod of diameter 10.01 cm at 19.9°C. Assume the average coefficients of linear expansion are constant. (a) To what temperature must the combination be cooled to separate the two metals? Brass=19 x 10^-6...

Thermal radiation question. Please help me explain the theory! I want to delete this post.

Homework Statement You cool a 100g slug of red-hot iron (temperature 745 degrees C) by dropping it into an insulated cup of negligible mass containing 85g of water at 20 degrees C. Assuming no heat exchange with the surroundings, what is the final temperature of the water? Homework...

Apparently, British researchers have discovered thermal vent ecosystems in the Antarctic Ocean. Of particular interest (to me, at least) was the discrepancy of species found around these events vs. thermal vents in all the other oceans of the world. There has always been some mystery as to...

Hi, Suppose a copper block is heated on one side so that one end is at 800K. Given the dimensions of the copper block, is there a way of calculating the temperature of a point in the block distance x from the heated end after a given time? With many thanks, Froskoy.

Homework Statement One end of a metal rod is maintained at 100 degrees C, and the other end is maintained at 0 degrees C by an ice-water mixture. The rod is 60 cm long and has a cross-sectional area of 1.25 cm^2. The heat conducted by the rod melts 8.50 g of ice in 10.0 min. Find the thermal...

Go easy on me, as I have no formal condensed matter education and just the highest undergraduate quantum physics and chemistry offered at my university. I read a lot of papers and did extra studying while taking those classes, but I'm definitely rusty on the mathematics. Feel free to give me...

Homework Statement At 5°c, a steel tank is 6m high, 9m in diameter, and contains oil to the 5.9m level. A heating coil is put into service, causing 3.4m^3 of oil to spill over the top of the tank by the time the final temperature is reached. Calculate the final temperature, if the coefficient...

According to my textbook... Thermal energy is the kinetic energy of the component particles of an object and is measured in joules. Heat is the thermal energy that is absorbed, given up or transferred from one object to another. But later on the book there is a small chapter called...

I am doing a zainy experiment at home. I need to devise a way of applying a cooling intensity factor (CIF) of around 70 mW/cm2. I need to cool material that is roughly 30 degrees Celsius down to around 2 degrees Celsius. The cooling has to last for a period of one hour or more. The surface...

thermal condution? little confusing can u please help to remove my doubt. According to law of thermal conduction dQ/dt=-kAdθ/x. variable have their usual meaning. first of all i want to know what is meaning of dQ/dt in this law?? If we see it in a cylindrical object with it's curved part...

Thermal Physics (Help me!) Following an engineering design, a building is constructed using a steel framework that is 50m high. How much taller is it on a summer day when the temperature is 38oC than on a -5oC winter day?

So, I had this idea for passive safety. Break-apart rods (zirconium with low-melting point metal inserts for example) which go through reactor core at regular intervals, are tensioned by springs, and in the event of overheating, are torn apart, operating simple (springs, latches) mechanisms to...

Homework Statement My problem is to calculate the Thermal stress of a Cylindric shell with inner radius a and outer radius b the inner surface is experiencing Temperature T1 and the outer surface is experiencing T2 with T1>T2 assuming that the linear thermal expansion coefficient is a, the...

Hi Physicsforums, I was trying to derive the formula that the coefficient for volume expansion, β, is 3 times the coefficient for length expansion, \alpha. As a reminder, the formulas are: \DeltaL = \alphaLo\DeltaT and \DeltaV = \betaVo\DeltaT where, supposedly, \beta = 3\alpha...

Hi there. Here is the deal. In my lab work, I've done experiments concerning on heat conduction. Now my professor had corrected my inform, and asked me a question for which I have no answer. I consulted for my work the book "heat conduction in solids" by H.S. Carslaw. The book says at the...

what exactly is elongation? in the thermal expansion question, it says if the elongation of the 2 rod fasten end to end is the same

I solved the problem and have the correct answer just not sure about something. Question:What will be the equilibrium temperature when a 274 g block of copper at 317°C is placed in a 137 g aluminum calorimeter cup containing 829 g of water at 13.0°C? So heat lost by copper = heat gained...

Homework Statement A 1-liter aluminum container at 20oC is filled with 0.975 liters of mercury at 20oC. If both the container and the mercury are heated, at what final temperature will the mercury completely fill the container? αAl = 24 × 10-6 (Cº)-1; βHg = 1.82×10-4 (°C)-1 Any help on...

Homework Statement Consider a bar of aluminum which is 10 cm X ½ m X 20 m. If the bar undergoes a change in its temperature from 10° C to 20° C, determine the new dimensions of the bar. Homework Equations ΔL=αL0ΔT α=24x10-6 The Attempt at a Solution I understand how the formula...

Hello, kinetic energy is in some cases a bit of a mystery to me, I've made several assumptions about these things. But some of those assumptions seem to conflict a bit with what seems to be happening, so I thought I'd throw these assumptions out here to maybe hear where I'm wrong. Any comments...

Homework Statement A vertical glass tube of length L = 1.2800000 is half-filled with a liquid at 20.0000* C. How much will the height of the liquid column change when the tube is heated to 30.0000*C? Glass linear expansion co = 1e-5/K Liquid volume expansion co = 4e-5/K Homework...

Homework Statement At 19°C, a rod is exactly 20.01 cm long on a steel ruler. Both the rod and the ruler are placed in an oven at 219°C, where the rod now measures 20.18 cm on the same ruler. What is the coefficient of linear expansion for the material of which the rod is made? Homework...

I have a question... Suppose you have a thin and long rectangular piece of aluminum. You heat one end (pt A). The thermal resistance (steady state) from one end (pt A) to the other (pt B) would be θ=ΔT/W Where W= Watts of heat energy. ΔT = temperature of ptA - temperature of ptB...

Why is this done? Wikipedia says that condensing the steam makes the cycle 'more efficient.' How is it more efficient? Why can't the de-energized steam be transferred to the boiler without condensing it?

Ok, I have some questions to answer for this lab report, and one of them has left me clueless. The experiment was as follows: An apparatus is made of a rectangular circuit (of known dimensions) of tubes filled with water with thermometers visible at various points throughout the circuit. No...

Homework Statement ""If the coefficient of thermal expansion of steel is 1.1 x 10^ -5 ℃^ -1 and a railway rail is 4. 5 m long, how much would the length Δ L of the rail increase by if the temperature changes from -10 ℃ to 30 ℃? "" Could anyone direct me to a youtube video, or something...

Homework Statement we have a metalic bar with thermal condutivity of 200w/(m*k) it has an area of 20 cm^2 which is in contact with with an heater that delivers 200 W and is at 300ºC. the metalic bar has a thickness of 1cm The two questions are: a) once the system have entered a...

Friction with the air is often neglected, but when traveling at Mach 18 it becomes a huge factor. To cope with this, NASA engineers have ingeniously developed sand-based thermal tiles that are designed to withstand temperatures that can reach up to 2600 degrees Fahrenheit. There are 3 types of...

I wish to design highly insulating structural load-bearing walls using local materials. Part of that effort requires an understanding of the dynamics of current insulation materials and why some are much higher in R-value while using the same base material. Part of my study so far suggests that...

I am trying to model the cooling of an object (for example, a sheet of glass) placed outside at night. At the moment I am only considering heat loss by radiation. I know that the net radiation from the object will be: Rnet = Robj - Rsky where: Rnet = the net radiation from the object...

Homework Statement In the diagram given, you pull upward on a rope that is attached to a cylinder on a vertical rod. Because the cylinder fits tightly on the rod, the cylinder slides along the rod with considerable friction. Your force does work (W = + 100 J) on the cylinder–rod–Earth system...

How do I go about deriving the thermal conductivity of graphene (specifically, in the low temperature limit) when I'm given the phonon dispersion relation? I haven't been able to find anything explaining how the dispersion relation relates to the thermal conductivity in materials. (this is...

Explain why the thermal expansion of a spherical shell made of a homogeneous solid is equivalent to that of solid sphere of the same material. I guess these equations would be of some help. (ΔA)=A*2α*(ΔT) α→ Coefficient of linear expansion. A→ Area T→ Temperature (ΔV)=V*3α*(ΔT)...

Hi group, I work at Thermal Vacuum Chamber, and we had an incident last night where our chamber, Which is 70' H x 30' D, was pumped down to a pressure of 3.7E-7. There was a release of gas into the chamber abruptly last night that caused the pressure in the chamber to rise to 5.0E-7, before it...

Rhodium has been measured and the following values have been obtained for the resonance parameters of a well-isolated resonance Eo=1.26 ev , σo=5000 b , Γ = 0.156 ev , σs=5.5 b , Is there anyone can help me HOW to calculate the thermal absorption cross section ? I'm disparate I don't know how to...

In wikipedia it says: "Thermal equilibrium is a theoretical physical concept, used especially in theoretical texts, that means that all temperatures of interest are unchanging in time and uniform in space." But isn't temperature defined because of the thermal equilibrium concept? It's defined...

In classical thermodynamics, if we dissipated the kinetic energy of an object as thermal energy, then we would increase the entropy. However, let's say we took 90% of some thermal energy in a reservoir, and converted it into work, and 10% of that is converted back into thermal energy after 1...

Homework Statement Consider a CO2 molecule, which is linear and has vibrational modes with frequency corresponding to 2565 cm-1 (an asymmetric stretch), 1480 cm-1 (a symmetric stretch) 526 cm-1 (bends). Sketch a curve showing how the constant volume heat capacity of CO2 gas varies with...

This is the question that I can't really answer 1. A cycle looks like an ellipse in the T-S diagram. The maximum and minimum temperatures are 1000K and 400K. The maximum and minimum entropies are 0.705 KJ/K and 0.235 Kj/K. Determine a. the heat added per cycle, b. the work produced per...

hay guys, A three-dimensional harmonic oscillator is in thermal equilibrium with a temperature reservoir at temperature T. Finde The average total energy of the oscillator I have no idea, how can I solve this problem, can you hint me please:rolleyes: