8 Steel balls 12 mm in diameter are annealed by heating to 1150 K and then slowly cooling to 400 K in an air envi- ronment for which T = 325 K and h = 20 W/m².K. Assuming the properties of the steel to be k = 40 W/m.K, p=7800 kg/m³, and c = 600 J/kg K, estimate the time required for the cooling process.

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A:

Q: Nitrogen gas has a heat capacity of 20.8 and 29.1 J/mol-C at constant volume and constant pressure…

A: Given Data: Specific heat capacity of N2 at constant Volume;Cv=20.8 J/mol °CSpecific heat capacity…

Q: Athin isothermal disk, having a diameter of 1.8 cm, is maintained at 40◦C and buried in a…

A: Given  thermal conductivity k= 0.8 W/m· ◦C  diameter of disk is D = 1.8 cm  radius = 0.9 cm = 0.009…

Q: A certain material has a thickness of 4 cm and its thermal conductivity is 0.04 W / m.oC. At a…

A: The heat flow rate at the given distances from the material is to be calculated.

Q: Example 2.1 : Calculate the rate of heat loss through a wall of k = 0.70 W/(m K)] 5 m in length, 4 m…

A: Above problem is based on conductio.Conduction is an mode of heat transfer which is define as the…

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A: Heat rate: Heat rate is defined as amount of heat (energy) per unit time. Unit of energy may be…

Q: The compression ratio of an air-standard dual cycle is 12, and the pressure at the beginning of…

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Q: A long circular cylinder is encased and centered in a long square cylinder of concrete (k 1.2 W/m·K)…

A: Given , Thermal conductivity,k=1.2W/mKTemperature of cylinder,T1=200°C=473KTemperature of…

Q: The pipe is 6 m long with an inner radius of 70 mm, an outer radius of 80 mm, and is made of…

A: The rate of heat transfer through the pipe wall is to be calculated.

Q: A spherical object at 10 °C was taken into a bath at 60 °C. The core temperature-time values ​​of…

A: Answer: Initial temperature of the spherical object, T0 = 10°C = 283 K Bath temperature, T∞ = 60°C =…

Q: 19.4 The fuel plates in a nuclear reactor are 4 ft long and stacked with a 1/2-in gap between them.…

A:

Q: 5. . . ) In a manufacturing process, a long, coated plastic rod (p = 2200 kg/m³, c = 800 J/kg K, k…

A: The time it take to the surface of the rod to reach 175o C, the temperature above which the special…

Q: A horizontal tube (inner and outside diameters are 2.0 cm and 2.5 cm respectively). is used as…

A: Given, 1Uinner=0.005 (m2–K)/W 1Uoutside=0.008 (m2–K)/W  1Uoverall=1Uinner+1Uoutside…

Q: Water available at 24 C is heated by a heating element having 30 mm outside diameter and 0.4 m…

A: Cp=4180J/kg.∘C k=0.64W/m∘C density(r)=988kg/m3 μ=0.55×10-3N-S/m2 Ts=80∘C length=0.4m do=30mm=0.03m…

Q: block (cube 10 cm aside) of ice is initially at a uniform temperature of -20°C. If it is placed over…

A: The heat transfer will occur from 5 faces as one is rest on plastic surface.To find the time…

Q: 8. For polytropic process the heat and work can not cross the boundary of the system * False True

A: Given, Concept of Polytropic Process Find,  For polytropic process the heat and work cannot cross…

Q: Air at 2 bar and 40°C is heated as it flows through tube of diameter 30mm at a velocity of 10 m/s.…

A: Given, Pressure P = 2 bar Velocity = 10 m/s

Q: Temperature difference is not the driving force for heat transfer. O yes O No

A: heat transfer is the change in thermal energy by difference in temperature of two body let say…

Q: Q.2 An Aluminum plate of area 500cm2 is heated up for 5 seconds and its temperature increases from…

A: Area of Aluminium Plate=500cm2=0.05m2 Thickness=2cm=0.02m Mass of Aluminium plate=3.46kg Time up to…

Q: Polymer laminates are formed by “squeezing” two flat sheets of polymer together under high pressure.…

A: To derive an expression for the temperature as a function of time and position in the two polymer…

Q: Q5) A cube of aluminum 10 cm on each side is initially at a temperature of 300 °C and is immersed in…

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Q: A certain matenial 2.5 em thick, with a cross-sectional area of 0.1 m, has one side maintained at…

A: Given, T3=95oC,T2=62oC,T1=35oC,∆x=0.025 m Assume Linear variation of thermal conductivity,…

Q: The rate of heat transfers through a wall of thickness 20 cm having k = 5 W/m K, inner surface…

A: Given: L = 20cm = 0.2m A = 1m2 T1 = 60oC T2 = 30oC k = 5W/mk

Q: 1. Assume steady-state conditions and a thermal conductivity of k 1.5 W/m-K. a. Determine the…

A: Heat Transfer: It is normally from a high-temperature object to a lower temperature object. This has…

Q: A piston-cylinder assembly has 1 kg of air at 700 kPa and 400C. The piston cross-sectional area is…

A: This problem is based on the concept of ideal gas law. The data given : Initial temperature ,T1 =…

Q: Q3) A 2-kW resistance heater wire with thermal conductivity of k 20 W/m - °C, a diameter of D = 5…

A: Given that- Resistance heater wire has total heat generation, Q=2 kW= 2000 W Thermal conductivity,…

Q: Consider that an iron is forgotten to be open throughout two days while its surface temperature is…

A: As given heat transfer is taking from iron to air ,it is a convection mode of heat transfer.…

Q: A 10 ft x 10 ft square sheet of steel one inch thick is at an initial temperature of 1100°F and is…

A: The thickness Length, Breadth, Time,

Q: Q3 ) A 2-kW resistance heater wire with thermal conductivity of k 20 W/m °C, a diameter of D = 5 mm,…

A: Resistance heater wire has total heat generation, Q=2 kW= 2000 WThermal conductivity, k=20…

Q: A thick cylindrical pipe with length of 1 m and an inner diameter of 20 mm and an outer diameter of…

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Q: Air with mass of 16 kg is heated at constant gage pressure of 9044 hPa from -24.0 °C to 184 °C.…

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Q: Prove that the dimensionless temperature through the Plane wall with heat generator is: T(X) - T(S)…

A: we need to determine the dimensionless temperature distribution in plane wall and prove the given…

Q: Convection heat transfer occurs between a fluid at rest and a bounding surface O when the two are at…

A: Convective heat transfer is the switch of heat between two our bodies via currents of moving gas or…