The surface area of an adult human is about 1.8 m 2 . Suppose a person with a skin temperature of 34°C is standing with bare skin in a room where the air is 25°C but the walls are 17°C. a. There is a “dead-air” layer next to your skin that acts as insulation. If the dead-air layer is 5.0 mm thick, what is the person's rate of heat loss by conduction ? b. What is the person’s net radiation loss to the walls? The emissivity of skin is 0.97. c. Does conduction or radiation contribute more to the total rate of energy loss? d. If the person is metabolizing food at a rate of 155 W, does the person feel comfortable, chilly, or too warm?
The surface area of an adult human is about 1.8 m 2 . Suppose a person with a skin temperature of 34°C is standing with bare skin in a room where the air is 25°C but the walls are 17°C. a. There is a “dead-air” layer next to your skin that acts as insulation. If the dead-air layer is 5.0 mm thick, what is the person's rate of heat loss by conduction ? b. What is the person’s net radiation loss to the walls? The emissivity of skin is 0.97. c. Does conduction or radiation contribute more to the total rate of energy loss? d. If the person is metabolizing food at a rate of 155 W, does the person feel comfortable, chilly, or too warm?
The surface area of an adult human is about 1.8 m2. Suppose a person with a skin temperature of 34°C is standing with bare skin in a room where the air is 25°C but the walls are 17°C.
a. There is a “dead-air” layer next to your skin that acts as insulation. If the dead-air layer is 5.0 mm thick, what is the person's rate of heat loss by conduction?
b. What is the person’s net radiation loss to the walls? The emissivity of skin is 0.97.
c. Does conduction or radiation contribute more to the total rate of energy loss?
d. If the person is metabolizing food at a rate of 155 W, does the person feel comfortable, chilly, or too warm?
Chemical pathways by which living things function, especially those that provide cellular energy, such as the transformation of energy from food into the energy of ATP. Metabolism also focuses on chemical pathways involving the synthesis of new biomolecules and the elimination of waste.
The surface area of an adult human is about 1.8 m2. Suppose a person with a skin temperature of 34°C is standing with bare skin in a room where the air is 25°C but the walls are 17°C.a. There is a “dead-air” layer next to your skin that acts as insulation. If the dead-air layer is 5.0 mm thick, what is the person’s rate of heat loss by conduction?b. What is the person’s net radiation loss to the walls? The emissivity of skin is 0.97.c. Does conduction or radiation contribute more to the total rate of energy loss?d. If the person is metabolizing food at a rate of 155 W, does the person feel comfortable, chilly, or too warm?
A solid metal cube has a length of 1 meter and across sectional area of 1 m2. What does it mean that the thermal conductivity of the metal is 170 W/(m °C)?
a. 170 W of heat would flow through the long direction if the block were 170 m long with a temperature difference of 1°C between its two ends.
b. 1 W of heat flows per 170 m2 cross sectional area when the temperature difference is 1°C.
c. It takes 170°C of temperature difference to cause1 W of heat to flow through the cube.
d. 170 W of heat flows through the cube when the temperature difference between the two sides is 1°C.
e. t takes 170 s for 1 W of heat to flow through the cube when the temperature difference is 1°C.
The change in temperature of a substance when heated, depends on its specific heat capacity.
a. If the specific heat capacity of lead is 120 j/kgk, what is the heat energy required to raise the tempreture of 0.50 kg of a lead ball from 25°C to 45°C?
b. The 0.50 kg lead ball at 45°C is now dropped into a calorimeter with water at 20°C. if the final temperature of the ball-water system is 25°C, what is the mass of the water?
Chapter 12 Solutions
College Physics: A Strategic Approach (3rd Edition)
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