A 0.03-in-thick copper plate (k = 223 Btu/h·ft·°F) is sandwiched between two 0.15-in-thick epoxy boards (k = 0.15 Btu/h·ft·°F) that are 7 in * 9 in in size. Determine the effective thermal conductivity of the board along its 9-in-long side. What fraction of the heat conducted along that side is conducted through copper?

In a physics lab, students are conducting an experiment to learn about the heat capacity of different materials. The first group is instructed to add a number of 1.50 g pellets made of lead, at a temperature of 92.0°C, to 305 g of water at 16.0°C. A second group is given the same number of 1.50 g pellets as the first group, but these are now aluminum pellets. Assume that no heat is lost to or gained from the surroundings for either group. (a) If the final equilibrium temperature of the lead pellets and water is 25.0°C, how many whole pellets did the first group use in the experiment? The specific heat of lead is 0.0305 kcal/(kg · °C). pellets (b) Will the final equilibrium temperature for the second group be higher, lower, or the same as for the first group? The specific heat of aluminum is 0.215 kcal/(kg · °C). O higher O lower O the same (c) What is the equilibrium temperature of the aluminum and water mixture for the second group? °C

An aluminum cup with mass 0.56 kg holds 0.96 kg of water. Both the cup and the water have a temperature of 10.°C. If a 0.76-kg piece of copper at 53.°C is added to the cup, what is the final equilibrium temperature in °C? You may assume that the cup, water, and copper are well insulated from anything else.

The thermal conductivities of human tissues vary greatly. Fat and skin have conductivities of about 0.20 W/m · K and 0.020 W/m · K respectively, while other tissues inside the body have conductivities of about 0.50 W/m · K. Assume that between the core region of the body and the skin surface lies a skin layer of 1.0 mm, fat layer of 0.50 cm, and 3.2 cm of other tissues. (a) Find the R-factor for each of these layers, and the equivalent R-factor for all layers taken together, retaining two digits. Rskin      m2 · K/W Rfat      m2 · K/W Rtissue      m2 · K/W R      m2 · K/W (b) Find the rate of energy loss when the core temperature is 37°C and the exterior temperature is 0°C. Assume that both a protective layer of clothing and an insulating layer of unmoving air are absent, and a body area of 2.0 m2. W

A student walking to class on a cold day (To = 4 °C) find a silver ring with an inner diameter of D = 1.85 cm. The silver has a coefficient of linear expansion of α = 18.6 × 10-6 1/C. a. Input an expression for the rings inner diameter Dh when the student warms it to their body temperature, Tb.  b. What is the change in diameter, in units of millimeters, if Tb = 37 °C?

The pipe 8 m long has an inner radius of 70 mm, an outer radius of 80 mm, and is made of stainless steel (k = 15 W / [m ° C]). The inner surface temperature is maintained at 180 ° C, and the outer surface is 30 ° C. At constant conditions and there is no heat generation from the pipe, calculate the heat transfer rate that occurs in the pipe wall. = watts