A concrete slab is 12.0 cm thick and has an area of 5.00 m2. Electric heating coils are installed under the slab to melt the ice on the surface in the winter months. What minimum power must be supplied to the coils to maintain a temperature difference of 20.0C between the bottom of the slab and its surface? Assume all the energy transferred is through the slab.

A large steam pipe is covered with a 4.80 cm thick insulating material with a thermal conductivity of 0.17 W/(m°C). How much energy is lost every second when the temperature of the steam inside the pipe is at 265 °C and the temperature outside of the pipe is 13.0 °C? The pipe has a diameter of 3.70 m and a length of 185 m. Neglect losses through the ends of the pipe. 3863.3 J

What is the rate of heat transfer in J/s through the body's skin and the fat layer just beneath its surface? Treat the skin and fat as a single layer that is 1.20 cm thick. Assume the temperature of the inner surface of the layer corresponds to internal body temperature, or 36.7 °C, and the temperature of the outer surface of the layer corresponds to skin temperature, or 34.0 °C. Take the total surface area of the layer to be 1.50 m² and use a value of 0.413 W/(m-C°) for the average thermal conductivity of the layer. Number Units

A Thermopane window of area 5 m² is con- structed of two layers of glass, each 4.4 mm thick separated by an air space of 3 mm. If the inside is at 11°C and the outside is at -24°C, what is the heat loss through the window? The thermal conductivity of glass is 0.8 W/m .° C and of air is 0.0234 W/m .° C. Answer in units of kW.

@ 2 O: F2 W S 8. An electric immersion heater has a power rating of 1900 W. If the heater is placed in a 1.8 kg of water at 30 °C, how many minutes will it take to bring the water to a boiling temperature? (Assume that there is no heat loss except to the water itself. Cwater=4186 J/kg.°C) min # 3 X 80 F3 E D $ 4 C F4 R TI F or do % 5 V F5 T G > 6 MacBook Air B F6 < H 887 & ◄◄ F7 U N * 8 J DII F8 M ( 9 K F9 O ) C L F10 (4) P F11 31 + 11 F12 18 BEL ?

Ice of mass 12.8 kg at 0°C is placed in an ice chest. The ice chest has 2.7 cm thick walls of thermal conductivity 0.07 W/m·K and a surface area of 1.29 m2. Express your answers with appropriate mks units. (a) How much heat must be absorbed by the ice during the melting process? (b) If the outer surface of the ice chest is at 39° C, how long will it take for the ice to melt?

An aluminum cup with mass 0.34 kg holds 0.36 kg of water. Both the cup and the water have a temperature of 12.°C. If a 0.13-kg piece of copper at 62.°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.

You drop an ice cube into an insulated flask full of water and wait for the ice cube to completely melt. The ice cube initially has a mass of 90.0 g and a temperature of 0°C. The water (before the ice cube is added) has a mass of 850 g and an initial temperature of 22.0°C. What is the final temperature (in °C) of the mixture? (Assume no energy is lost to the walls of the flask, or to the environment.)  °C

A 50.0-g piece of brass (specific heat 380 J/kg K) is heated to 90.0° C and immersed in 100 g of water (specific heat 4184 J/kg K), initially at 15.0° C c. The well-insulated container is then sealed and allowed to reach thermal equilibrium. What is the final temperature of the system? 18.3° C 13.7° С 24.8° C 36.3° C 12.9° C

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