The R-value of insulation is a measure of its ability to resist heat transfer. For fiberglass insulation, 3 1 2 inches is rated at R-11 and 6 inches is rated at R-19. Assuming that this relationship is linear, write the equation that gives the R-value of fiberglass insulation R as a function of its thickness t (in inches)

The R-value of insulation is a measure of its ability to resist heat transfer. For fiberglass insulation, 3 1 2 inches is rated at R-11 and 6 inches is rated at R-19. Assuming that this relationship is linear, write the equation that gives the R-value of fiberglass insulation R as a function of its thickness t (in inches)

University Physics Volume 2

18th Edition

ISBN:9781938168161

Author:OpenStax

Publisher:OpenStax

Chapter1: Temperature And Heat

Section: Chapter Questions

Problem 100P: One easy way to reduce heating (and cooling) costs is to add extra insulation in the attic of a...

See similar textbooks

Similar questions

Compare the SI units of specific heat and latent heat and explain any differences.
One easy way to reduce heating (and cooling) costs is to add extra insulation in the attic of a house. Suppose a single-story cubical house already had 15 cm of fiberglass insulation in the attic and in all the exterior surfaces. If you added an extra 8.0 cm of fiberglass to the attic, by what percentage would the heating cost of the house drop? Take the house to have dimensions 10 m by 15 m by 3.0 m. Ignore air infiltration and heat loss through windows and doors, and assume that the interior is uniformly at one temperature and the exterior is uniformly at another.
Calculate the length of a 1-meter rod of a material with thermal expansion coefficient when the temperature is raised from 300 K to 600 K. Taking your answer as the new initial length, find the length after the rod is cooled back down to 300 K. Is your answer 1 meter?
In the heating seasons the heat loss from a building (and thus the heating cost) is strongly dependent on the difference between the indoor and outdoor temperature. If the average outdoor temperature in a particular city during the heating season is 45 F (7 C), what is the effect on heating cost percentage-wise if the thermostat setting is fixed at 74 F (23.3 F) instead of 68 F (20 C)?
The quantity of energy Q transferred by heat conduction through an insulating pad in time interval Δt is described by Q/Δt = κAΔT/d, where κ is the thermal conductivity of the material, A is the face area of the pad (perpendicular to the direction of heat flow), ΔT is the difference in temperature across the pad, and d is the thickness of the pad. In one trial to test material as lining for sleeping bags, 86.0 J of heat is transferred through a 3.40-cm-thick pad when the temperature on one side is 37.0°C and on the other side is 2.00°C. In a trial of the same duration with the same temperatures, how much heat will be transferred when more of the material is added to form a pad with the same face area and total thickness 8.41 cm?
Following vigorous exercise, the body temperature of an77-kg person is 42 degrees celcius. At what rate in watts must the person transfer thermal energy to reduce the body temperature to in 36 degress celcius in 30 min, assuming the body continues to produce energy at the rate of132 W?
What is the rate of heat transfer by radiation, with an unclothed person standing in a dark room whose ambient temperature is 22.0ºC . The person has a normal skin temperature of 33.0ºC and a surface area of 1.50 m2 . The emissivity of skin is 0.97 in the infrared, where the radiation takes place.
A hot steel plate with a surface area of 2.47 m2 and a constant surface temperature of 161°C is exposed to ambient air at 23°C. If the convection heat transfer coefficient is 18.2 W/m2· K, what is the rate of heat transfer (in W) from the plate to the air [round your final answer to zero decimal places]?
An engineer who is working on the heat transfer analysis of a house in English units needs the convection heat transfer coefficient on the outer surface of the house. But the only value he can find from his handbooks is 22 W/m2·K, which is in SI units. The engineer does not have a direct conversion factor between the two unit systems for the convection heat transfer coefficient. Using the conversion factors between W and Btu/h, m and ft, and °C and °F, express the given convection heat transfer coefficient in Btu/h·ft2·°F.
Compute the heat transfer through the air condition if the outside temperature is outside temperature, To = 5 degrees Celsius, inside temperature = 20 degrees Celsius, in a room with length 5 m, width of 6 m and height of 4 m. A typical volume flow for ventilation is 20 liters/second or 0.02 cubic meter/s, how much time will it take to replace all air within this room? Then, compute total thermal power flux out of the room through the ventilation? Given, Cp = 1005 J/khK, and roho = 1.2 kg/cubic.
When the indoor temperature of a house is 25°C and the outdoor temperature is -8°C, the inside and outside surfaces of the glass are measured to be 21.4°C and 18.1°C. If the glass has an area of 3.06 m2 and a thickness of 6.23 mm, what is the rate of heat (in W) lost though the window [round your final answer to zero decimal places]? {kglass = 0.78 W/m∙K}
A body whose surface area is 0.2 m2, emissivity is 0.8, and temperature is 100°C is placed in a large, evacuated chamber whose walls are at 25°C. What is the rate at which radiation is emitted by the surface, in W? What is the net rate at which radiation is exchanged between the surface and the chamber walls, in W?