BIO Evaporation of sweat is an important mechanism for temperature control in some warm-blooded animals. (a) What mass of water must evaporate from the skin of a 70.0-kg man to cool his body 1.00 C°? The heat of vaporization of water at body temperature (37°C) is 2.42 × 10 6 J/kg. The specific heat of a typical human body is 3480 J/kg · K (see Exercise 17.25). (b) What volume of water must the man drink to replenish the evaporated water? Compare to the volume of a soft-drink can (355 cm 3 ).
BIO Evaporation of sweat is an important mechanism for temperature control in some warm-blooded animals. (a) What mass of water must evaporate from the skin of a 70.0-kg man to cool his body 1.00 C°? The heat of vaporization of water at body temperature (37°C) is 2.42 × 10 6 J/kg. The specific heat of a typical human body is 3480 J/kg · K (see Exercise 17.25). (b) What volume of water must the man drink to replenish the evaporated water? Compare to the volume of a soft-drink can (355 cm 3 ).
BIO Evaporation of sweat is an important mechanism for temperature control in some warm-blooded animals. (a) What mass of water must evaporate from the skin of a 70.0-kg man to cool his body 1.00 C°? The heat of vaporization of water at body temperature (37°C) is 2.42 × 106 J/kg. The specific heat of a typical human body is 3480 J/kg · K (see Exercise 17.25). (b) What volume of water must the man drink to replenish the evaporated water? Compare to the volume of a soft-drink can (355 cm3).
A 6.25 kg block ice at 0 degrees Celsius is being warmed on a glass stove top. The thermal conductivity of the glass is 1.00 W/ (m K) and the glass is 0.50 cm thick. If the radiator plate underneath the glass raises the temperature of the bottom of the glass to 125 degrees Celsius, how long would it take to completely melt the ice? Assume the ice remains a solid rectangle with a square base of side 15 cm as it melts.
B. What is the rate of entropy change in Joules/ Kelvin/ seconds of the melting ice?
a) A house walls that are 11 cm thick and have an average thermal conductivity four times that of glass wool. Assume there are no windows or doors. The walls’ surface area is 850000 cm2 and their inside surface is at 18°C, while their outside surface is at 7°C. (Thermal conductivity of glass wool is 0.042 W/m°C)
(i) Calculate the rate of heat conduction through house walls?
Answer for part 1
(ii) How many 150W room heaters would be needed to balance the heat transfer due to conduction? (approximate number)
Answer for part 2
b) A spherical infrared heater of radius 5.1 cm has an emissivity of 0.8. What temperature must it run at if the required power is 0.56 kW? Neglect the temperature of the environment. (Stefan's constant = 5.67*10-8 Wm-2K-4)
The temperature of the heater in Celsius =
01)
A. An ice cube of mass 60 g is taken from a freezer at -15 °C and dropped into 100 g of water at 80°C. What will be the final temperature of the mixture? The specific heat capacity of ice is 2.04 kJ/kg °C · specific latent heat of fusion of ice is 334 kJ/kg, the specific heat capacity of water is 4.18 kJ/kg/°C
B. A sphere of radius 0.500 m, temperature 27.0 C, and emissivity 0.850 is located in an environment of temperature 77.0 C. At what rate does the sphere (a) emit and (b) absorb thermal radiation? (c) What is the sphere’s net rate of energy exchange? (Stefan Boltzmann constant) = 5.67 x 10–8 W/m2 K4
C. A copper rod 24 cm long has cross-sectional area of 4 cm2. One end is maintained at 24°C and the other is at 184°C. What is the rate of heat flow in the rod? The heat Conductivity of copper is 397 W/m · °C.
D. Below picture shows the composite wall block diagram. Calculate the thermal resistance of each blocks of A, B and C. Draw the thermal circuit diagram for the below…
Chapter 17 Solutions
University Physics with Modern Physics (14th Edition)
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