A poker is a stiff, nonflammable rod used to push burning logs around in a fireplace. Suppose it is to be made of a single material. For best functionality and safety, should the poker be made from a material with (a) high specific heat and high thermal conductivity, (b) low specific heat and low thermal conductivity, (c) low specific heat and high thermal conductivity, (d) high specific heat and low thermal conductivity, or (e) low specific heat and low density?

A small metal cube with a thermal mass mc and an initial temperature 0 is dropped into a container of water that is actively maintained at a constant temperature 0w. The cube quickly comes to rest on the bottom surface of the container. The bottom surface is maintained at a constant temperature 0 (note that this is different from 0w). The thermal resistance between the cube and the water is Rcw while the thermal resistance between the bottom surface of the container and the cube is RCB. The temperature of the cube is denoted by 0c. a) Draw the system schematic indicating the assumed directions of the heat transfer rates. Label all the nodes and system parameters. b) Derive the governing equation for the temperature of the cube, 0c. c) Where does to appear in the system schematic and how does it affect the governing equations? d) Calculate the steady-state temperature of the cube, css, assuming the following system parameters: 0o = 21°C, 0B = 6°C, 0w = 0°C, Rcw = 2°C/W, and RCB = 4°C/W

A 155 g copper bowl contains 230 g of water, both at 20.0°C. A very hot 300 g copper cylinder is dropped into the water, causing the water to boil, with 4.05 g being converted to steam. The final temperature of the system is 100°C. Neglect energy transfers with the environment. (a) How much energy (in calories) is transferred to the water as heat? 8.6 X kcal (b) How much energy (in calories) is transferred to the bowl? 55 X kcal (c) What is the original temperature of the cylinder? 553.6 X °C Did you use the idea of conservation of energy? That is, did you equate the sum of the energy transfers to zero? For the bowl and cylinder, did you substitute the expression relating an energy transfer, the specific heat, the mass, and the temperature change? For the water, did you use the same expression to get the water to the boiling point? Did you also include an expression for the heat of vaporization? Did you use the given final temperature for each of the three materials?

A wood stove is used to heat a single room. The stove is cylindrical in shape, with a diameter of 40.0 cm and a length of 55.0 cm, and operates at a temperature of 410°F. (o = 5.6696 x 108 w/m2 . K, 1 Btu = 1054 J.) (a) If the temperature of the room is 70.0°F, determine the amount of radiant energy delivered to the room by the stove each second if the emissivity is 0.950. (b) If the room is a square with walls that are 8.00 ft high and 30.0 ft wide, determine the R-value needed in the walls and ceiling to maintain the inside temperature at 70.0°F if the outside temperature is 32.0°F. Note that we are ignoring any heat conveyed by the stove via convection and any energy lost through the walls (and windows!) via convection or radiation. ft2. oF . h/Btu