Q: A 9-cm-diameter potato (ρ=1100 kg
A 9-cm-diameter potato (ρ=1100 kg/m3, cp =3900 J/kg⋅K, k = 0.6 W/m⋅K, and α = 1.4 × 10−7 m2/s) that is initially at a uniform temperature of 25°C is baked in an oven at 170°C until a temperature senso...
See AnswerQ: In Betty Crocker’s Cookbook, it is stated that it takes 2
In Betty Crocker’s Cookbook, it is stated that it takes 2 h 45 min to roast a 3.2-kg rib initially at 4.5°C to “rare” in an oven maintained at 163°C. It is recommended that a meat thermometer be used...
See AnswerQ: Repeat Prob. 18–64 for a roast rib that is
Repeat Prob. 18–64 for a roast rib that is to be “welldone” instead of “rare.” A rib is considered to be well-done when its center temperature reaches 77°C, and the roasting in this case takes about 4...
See AnswerQ: Under what conditions can a plane wall be treated as a semi
Under what conditions can a plane wall be treated as a semi-infinite medium?
See AnswerQ: What is a semi-infinite medium? Give examples of solid
What is a semi-infinite medium? Give examples of solid bodies that can be treated as semi-infinite media for heat transfer purposes.
See AnswerQ: Consider a hot semi-infinite solid at an initial temperature of
Consider a hot semi-infinite solid at an initial temperature of Ti that is exposed to convection to a cooler medium at a constant temperature of T∞, with a heat transfer coefficient of h. Explain how...
See AnswerQ: Consider a classroom for 55 students and one instructor, each generating
Consider a classroom for 55 students and one instructor, each generating heat at a rate of 100 W. Lighting is provided by 18 fluorescent lightbulbs, 40 W each, and the ballasts consume an additional 1...
See AnswerQ: The walls of a furnace are made of 1.5-
The walls of a furnace are made of 1.5-ft-thick concrete (k = 0.64 Btu/h⋅ft⋅°F and α = 0.023 ft2/h). Initially, the furnace and the surrounding air are in thermal equilibrium at 70°F. The furnace is t...
See AnswerQ: Consider heat transfer between two identical hot solid bodies and their environments
Consider heat transfer between two identical hot solid bodies and their environments. The first solid is dropped in a large container filled with water, while the second one is allowed to cool natural...
See AnswerQ: Consider a curing kiln whose walls are made of 30-cm
Consider a curing kiln whose walls are made of 30-cm thick concrete with a thermal diffusivity of α=0.23 × 10−5 m2/s. Initially, the kiln and its walls ar...
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