Referring to Problem P3.23 and Table 3.5, if the units for c p and are Btu/(slug

Referring to Problem P3.23 and Table 3.5, if the units for c_p and µ are Btu/(slug · °F) and slug/(ft · h), respectively, what must be the USCS units of thermal conductivity in the definition of Pr?

Table 3.5

Problem P3.23

Convection is the process by which warm air rises and cooler air falls. The Prandtl number (Pr) is used when mechanical engineers analyze certain heat transfer and convection processes. It is defined by the equation

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Quantity Derived Unit Abbreviation Definition Length mil mil 1 mil = 0.001 in. inch in. 1 in. = 0.0833 ft mile mi 1 mi = 5280 ft 1 gal = 0.1337 ft 1 slug = 1 (lb s)/ft Volume gallon gal Mass slug slug 1 lbm = 3.1081 x 10-2 (Ib s')/ft pound-mass Ibm Force ounce OZ 1 oz = 0.0625 lb ton 1 ton = 2000 lb ton Torque, or moment of a force ft . Ib foot-pound Pressure or stress pound/inch? psi 1 psi = 1 lb/in? Energy, work, or heat foot-pound ft Ib British thermal Btu 1 Btu 778.2 ft · Ib unit Power horsepower hp 1 hp = 550 (ft · Ib)/s Temperature degree Fahrenheit °F = °R – 459.67 °F Although a change in temperature of 1° Rankine also equals a change of 1° F, numerical values are converted using the formula.