3. Assume that the thickness of the tissue between the interior and the exterior of the body is d =3 cm and that the average area through which conduction can occur is A =1.5 m². Find heat transferred by conduction per hour if temperature difference between the inner body and the skin is AT = 2°C. Coefficient of thermal for tissue without blood is K. = 18 × 10-2 Cal /m-hr-°C.

3. Assume that the thickness of the tissue between the interior and the exterior of the body is d =3 cm and that the average area through which conduction can occur is A =1.5 m². Find heat transferred by conduction per hour if temperature difference between the inner body and the skin is AT = 2°C. Coefficient of thermal for tissue without blood is K. = 18 × 10-2 Cal /m-hr-°C.

College Physics

1st Edition

ISBN:9781938168000

Author:Paul Peter Urone, Roger Hinrichs

Publisher:Paul Peter Urone, Roger Hinrichs

Chapter14: Heat And Heat Transfer Methods

Section: Chapter Questions

Problem 39PE: Suppose a person is covered head to foot by wool clothing with average thickness of 2.00 cm and is...

See similar textbooks

Similar questions

A glass coffee pot has a circular bottom with a 9.00-cm diameter in contact with a heating element that keeps the coffee warm with a continuous heat transfer rate of 50.0 W (a) What is the temperature of the bottom of the pot, if it is 3.00 mm thick and the inside temperature is 60.0C ? (b) If the temperature of the coffee remains constant and all of the heat transfer is removed by evaporation, how many grams per minute evaporate? Take the heat of vaporization to be 2340kJ/kg.
For the human body, what is the rate of heat transfer by conduction through the body’s tissue with the following conditions: the tissue thickness is 3.00 cm, the change in temperature is 2.00C, and the skin area is 1.50m2. How does this compare with the average heat transfer rate to the body resulting from an energy intake of about 2400 kcal per day? (No exercise is included.)
A granite ball of radius 2.00 m and emissivity 0.450 is heated to 135C. (a) Convert the given temperature to Kelvin. (b) What is the surface area of the ball? (c) If the ambient temperature is 25.0C, what net power does the ball radiate?
What is me Fahrenheit temperature of a person with at 39.0°C fever?
(a) The number of kilocalories in food is determined by calorimetry techniques in which the food is burned and the amount of heat transfer is measured. How many kilocalories per gram ale there in a 5.00-g peanut if the energy from burning it is transferred to 0. 500 kg of water held in a 0.100-kg aluminum cup, causing a 54.9- temperature increase? Assume the process takes place in an ideal calorimeter, in other words a perfectly insulated container. (b) Compare your answer to the following labeling information found on a package of dry roasted peanuts: a sewing of 33 g contains 200 calories. Comment on whether the values are consistent.
A high-end gas stove usually has at least one burner rated at 14 000 Btu/h. (a) If you place a 0.25-kg aluminum pot containing 2.0 liters of water at 20.C on this burner, how long will it take to bring the water to a boil, assuming all the heat from the burner goes into the pot? (b) Once boiling begins how much time is required to boil all the water out of the pot?
Calculate the rate of heat conduction out of the human body, assuming that the core internal temperature is 37.0C, the skin temperature is 34.0C, the thickness of the tissues between averages 1.00 cm, and the surface area is 1.40m2.
(a) How much heat transfer is required to raise the temperature of a 0.750kg aluminum pot containing 2.50 kg of water from 30.0C to the boiling point and then boil away 0.750 kg of water? (b) How long does this take if the rate of heat transfer is 500 W 1watt=ljoule/second(lW=lJ/s) ?
In 1986, a gargantuan iceberg broke away from the Ross Ice Shelf in Antarctica. It was approximately a rectangle 160 km long, 40.0 km wide, and 250 m thick. (a) What is the mass of this iceberg, given that the density of ice is 917kg/m3 ? (b) How much heat transfer (in joules) is needed to melt it? (c) How many years would it take sunlight alone to melt ice this thick, if the ice absorbs an average of 100W/m2, 12.00 h per day?
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 sin face 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. (b) Find the rate of energy loss when the core temperature is 37C and the exterior temperature is 0C. Assume that both a protective layer of clothing and an insulating layer of unmoving air a absent, and a body area of 2.0 m2.
A person inhales and exhales 2.00 L of 37.0C air, evaporating 4.00102g of water from the lungs and breathing passages with each breath. (a) How much heat transfer occurs due to evaporation in each breath? (b) What is the rate of heat transfer in watts if the person is breathing at a moderate rate of 18.0 breaths per minute? (c) If the inhaled air had a temperature of 20.0C, what is the rate of heat transfer for warming the air? (d) Discuss the total rate of heat transfer as it relates to typical metabolic rates. Will this breathing be a major form of heat transfer for this person?
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 sin face 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. (b) Find the rate of energy loss when the core temperature is 37C and the exterior temperature is 0C. Assume that both a protective layer of clothing and an insulating layer of unmoving air a absent, and a body area of 2.0 m2.