A Slab of Concrete and an Insulating Board Are in Thermal

question 19

Multiple Choice

A slab of concrete and an insulating board are in thermal contact with each other. The temperatures of their outer surfaces are 68°F and 50°F. Determine the rate of heat transfer (in BTU/ft2⋅h) if the R values are 1.93 and 8.7 ft2⋅°F⋅h/BTU, respectively.

• A)9.7
• B)2.5
• C)5.3
• D)1.7
• E)28

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Definitions:

Genetic Variation

Inherited differences among individuals.

Identical Halves

Describes an organism or structure that can be divided into two equal parts that are mirror images of each other, typical of radial symmetry.

Metabolism

The sum of all the chemical processes that occur within a cell or organism; the transformations by which energy and matter are made available for use by the organism. See anabolism and catabolism.

Chemical Reactions

Processes that involve rearrangement of the molecules or ionic structure of substances, resulting in the formation of new products.