y buddy is starting to get hypothermic (body temperature 306 K) during an epic backcountry ski adventure. Since I'm quite warm (body temperature 310 K), I decide to get in a sleeping bag with him to try and warm him up. What heat transfer mechanism will be most responsible for heating him up? For simplicity, ignore any internal temperature differences across my body (that is, assume my skin temperature is also 310 K). Use numbers to support your answer (for human skin, you can use th

y buddy is starting to get hypothermic (body temperature 306 K) during an epic backcountry ski adventure. Since I'm quite warm (body temperature 310 K), I decide to get in a sleeping bag with him to try and warm him up. What heat transfer mechanism will be most responsible for heating him up? For simplicity, ignore any internal temperature differences across my body (that is, assume my skin temperature is also 310 K). Use numbers to support your answer (for human skin, you can use th

Principles of Heat Transfer (Activate Learning with these NEW titles from Engineering!)

8th Edition

ISBN:9781305387102

Author:Kreith, Frank; Manglik, Raj M.

Publisher:Kreith, Frank; Manglik, Raj M.

Chapter1: Basic Modes Of Heat Transfer

Section: Chapter Questions

Problem 1.77P: 1.77 Explain each in your own words. (a) What is the mode of heat transfer through a large steel...

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V:01 Expert Q&A Done Question 1: In your own words, write down the differences between thermodynamic and heat transfer. (3 Marks) Question 2: Estimate the heat loss per square metre of surface through a brick wall 0.5 m thick when the inner surface is at 400 K and the outside surface is at 300 K. The thermal conductivity of the brick may be taken as 0.7 W/mK. (2 Marks) Question 3: A furnace is constructed with 0.20 m of firebrick, 0.10 m of insulating brick, and 0.20 m of building brick. The inside temperature is 1200 K and the outside temperature is 330 K. If the thermal conductivities are as shown in the figure below, estimate the heat loss per unit area. (5 Marks) 1200 K 330 K Insulating brick X-0.10m k= 0.21 Ordinary brick X=0.20 m Fire brick X= 0.20 m k= 1.4 k= 0.7 (W/mK)
When the sun is high in the sky, it delivers approximately 1000 watts of power to each square meter of earth's surface. The temperature of the surface of the sun is about 6000 K, while that of the earth is about 300 K. Suppose you plant grass on this square meter of earth. Some people might argue that the growth of the grass (or of any other living thing) violates the second law of thermodynamics, because disorderly nutrients are converted into an orderly life form. How would you respond?
The following graph shows the thermal behavior of 2 kg of a material called Uniandesato undergoing a solid-liquid phase transition. In a container, thermally insulated from the outside, 20 kg of liquid water at a temperature of 80°C are placed. In addition to this, an unknown amount of Uniandesato in a 100% solid state at its melting temperature (10°C) is added. The specific heat of water is 4186 J/kg°C. a) If the system reaches an equilibrium temperature of 60°C, calculate the initial amount of Uniandesato added to the container. b) Calculate the change in entropy during this process and show that it is consistent with the Second Law of Thermodynamics. Hint: Extract the necessary information to solve this problem from the graph.
The left side of this equation tells how much energy Q the cylinder gives to the water while it cools. The right side of this equation tells how much energy Q the water and aluminum cup absorb from the cylinder to warm up. Because it is the same energy, they are equal. What is known in this equation? Mcyl 411.7 g, malum 46.5 g, malum+water = 175 g Can you find: mwater =? g Twater = Talum = 20°C (water and cup of room temperature) 90°C, T; = 35°C (hot cylinder and cool "cylinder+cup+water" temperatures) Tcyl kCal Calum = 0.22, Cwater 1 (specific heat of water and aluminum, measured in units kg-°C What are we looking for is Ccul - How we find it? Plug all the numbers into the equation (1), Ccul will be one unknown which you can calculate from the equation. Important, convert all the masses from grams to kilograms! After you find Ccyl, compare it to known value for the copper 0.093(our cylinder is made out of copper). |Ceyl -0.093| % : · 100% 0.093
In a concentrated solar power plant, molten salt tank is used to store the thermal energy from the sun during the day. The tank wall thickness is 3cm containing molten salt at a temperature of 390 degree Celsius. There is atmospheric air outside the tank at a temperature of 30 degree Celsius. Suppose heat is lost as a result of heat transfer from the molten salt to the atmospheric air. What is the mode of heat transfer in this condition? conduction then convection convection then conduction convection then conduction then convection conduction then convection then conduction
Hello. Can you please help answer the question shown in the photo? It is a 3-part question which I have attempted many times. I was able to calculate the correct answer for part 2, but part 1 and part 3 still says I am incorrect. Please show how to properly solve the problem. The topic is heat transfer. Thank you.
Completely solve and box the final answer. Write legibly 3. Determine the heat loss in KW of a vertical furnace made up of inner wall of firebrick 28 cm thick followed by insulating brick 18 cm thick and an outer wall of steel 1.5 cm thick. Surface temperature of the wall adjacent to the combustion chamber is 895ºC while that of the outer surface of steel is 42ºC. Use a thermal conductivity of wall in W/m-ºK for firebrick, insulating brick and steel to be 14, 0.92, and 52 respectively. The cross section is 2.5 m x 7.5 m.
Determine the heat conduction of a boiler if you are given the following data: The thickness of the boiler is 15 cm, the T1 is the temperature of the water is 25°C and the T2 of the steam is 110°C, the thermal conductivity The boiler material is iron (use presentation table), the boiler area is 4.5 m^2
Substance Steam water Ice ⇒ water Show Transcribed Text S Answer the following questions dealing with methods of heat transfer. Latent Heat (J/kg) 2,260,000 333,000 Show Transcribed Text S Ice of mass 10.1 kg at 0°C is placed in an ice chest. The ice chest has 2.5 cm thick walls of thermal conductivity 0.01 W/m-K and a surface area of 1.23 m². Express your answers with appropriate mks units. (a) How much heat must be absorbed by the ice during the melting process? (b) If the outer surface of the ice chest is at 37° C, how long will it take for the ice to melt? Ĉ
After a thorough derivation by Doraemon to establish an equation for cylindrical fuel rod of a nuclear reactor. Here he was able to come up an equation of heat generated internally as shown below. 96 = 9. where qG is the local rate of heat generation per unit volume at radius r, ro is the outside radius, and qo is the rate of heat generation per unit volume at the centre line. Calculate the temperature drop from the centre line to the surface for a 2.5 cm outer diameter rod having k = 25 W/m K, if the rate of heat removal from the surface is 1650 kW/m2 A 619 °C 719 °C C) 819 °C 919 °C E 1019 °C F None of these
The thermal conductivities of wood is kwood = 0.1W/(m°C)and air is kair = 0.0234W/(m°C). Part A If the temperature of the room is 20°C and outside is 10°C, find the rate of heat flow for a wall of wood with area = 10 m² and thickness of 5cm. O 60 W O 304 W O 34 W O 200 W O 100 W Submit Request Answer Part B The wall of wood with thickness of 5cm is now replaced with two layers of wood and a gap of air between the wood. Each layer of wood has a 2.5cm thickness and the gap is 1cm. The rate of heat flow will, decreases. increases. stay the same. Submit Request Answer Part C The temperature in the air gap will be, O 20°C, between 10°C and 20°C, O 10°C,
Let's say a 3.0 gram copper wafer is dropped from a height of 50.0 meters. If 60% of the potential energy lost in the drop could be converted to thermal energy used to heat the copper from an initial temperature of 25 degrees celsius, what would the final temperature of the copper wafer? Would the answer be different if the wafer has a mass greater than 3 grams? Note: the specific heat of copper is 387 J/(kg*K). The temperature is between 25.8 and 26.0 degrees celsius, yes the bigger the mass the greater the energy. O The temperature is between 25.6 and 25.8 celsius, answer does not depend on mass. O The temperature is between 25.0 and 25.2 celsius, answer does not depend on mass. O The temperature is 25.5 and of course the more mass something has the greater energy will be needed to raise the temperature. The temperature is 26.2 and if the mass is doubled so will be the change in temperature. O The temperature is 25.9 degrees celsius and the answer does not depend on mass. O The…