Two neighbors, Mr. Jones and Mr. Rogers, each have identical size, same amount of water, etc.). One day, Mr. Jones heats his pool using a highly efficient solar panel from T=18°C to T=21°C. That same day Mr. Rogers uses an old, inefficient natural gas heater to heat his pool from T=20°C to T=23°C. Mr. Jones brags to Mr. Rogers that since the solar panel is more efficient than the mechanical heater, he has added less energy to his pool than Mr. Rogers has. We assume that both pools have a very efficient “insulating blanket over the water surface, so they lose insignificant heat to the environment. Should Mr. Rogers believe Mr. Jones? Explain why or why not using mot

Two neighbors, Mr. Jones and Mr. Rogers, each have identical size, same amount of water, etc.). One day, Mr. Jones heats his pool using a highly efficient solar panel from T=18°C to T=21°C. That same day Mr. Rogers uses an old, inefficient natural gas heater to heat his pool from T=20°C to T=23°C. Mr. Jones brags to Mr. Rogers that since the solar panel is more efficient than the mechanical heater, he has added less energy to his pool than Mr. Rogers has. We assume that both pools have a very efficient “insulating blanket over the water surface, so they lose insignificant heat to the environment. Should Mr. Rogers believe Mr. Jones? Explain why or why not using mot

Name: Use energy transfers and conservation (energy interaction model 5. Tw
Uploaded: 2024-03-20T06:57:16.000Z
Channel: Bartleby
Description: Use energy transfers and conservation (energy interaction model 5. Two neighbors, Mr. Jones and Mr. Rogers, each have identical swimming pools (samesize, same amount of water, etc.). One day, Mr. Jones heats his pool using a highlyefficient solar pa

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 41PE: One easy way to reduce heating (and cooling) costs is to add extra insulation in the attic of a...

See similar textbooks

Similar questions

One way to cool a gas is to let it expand. When a certain gas under a pressure of 5.00 106 Ha at 25.0C is allowed to expand to 3.00 times its original volume, its final pressure is 1.07 106 Pa. (a) What is the initial temperature of the gas in Kelvin? (b) What is the final temperature of the system? (See Section 10.4.)
One easy way to reduce heating (and cooling) costs is to add extra insulation in the attic of a house. Suppose the 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, then by what percentage would the heating cost of the house drop? Take the single story house to be of dimensions 10 m by 15 m by 3.0 m. Ignore air infiltration and heat loss through windows and doors.
(a) How much heat transfer is required to raise the temperature of a 0.750-kg aluminum pot containing 2.50 kg of water from 30.0 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?
The surface area of an unclothed person is 1.50 m2, and his skin temperature is 33.0C. The person is located in a dark room with a temperature of 20.0C, and the emissivity of the skin is e = 0.95. (a) At what rate is energy radiated by the body? (b) What is the significance of the sign of your answer?
Assume you are measuring the specific heat of a sample of originally hot metal by using a calorimeter containing water. Because your calorimeter is not perfectly insulating, energy can transfer by heat between the contents of the calorimeter and the room. To obtain the most accurate result for the specific heat of the metal, you should use water with which initial temperature? (a) slightly lower than room temperature (b) the same as room temperature (c) slightly higher than room temperature (d) whatever you like because the initial temperature makes no difference
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?
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.
At our distance from the Sun, the intensity of solar radiation is 1 370 W/m2. The temperature of the Earth is affected by the greenhouse effect of the atmosphere. This phenomenon describes the effect of absorption of infrared light emitted by the surface so as to make the surface temperature of the Earth higher than if it were airless. For comparison, consider a spherical object of radius r with no atmosphere at the same distance from the Sun as the Earth. Assume its emissivity is the same for all kinds of electromagnetic waves and its temperature is uniform over its surface. (a) Explain why the projected area over which it absorbs sunlight is r2 and the surface area over which it radiates is 4r2. (b) Compute its steady-state temperature. Is it chilly?
In cold climates, including the northern United States, a house can be built with very large windows facing south to take advantage of solar heating. Sunlight shining in during the daytime is absorbed by the floor, interior walls, and objects in the room, raising their temperature to 38.0C. If the house is well insulated, you may model it as losing energy by heat steadily at the rate 6 000 W on a day in April when the average exterior temperature is 4C and when the conventional heating system is not used at all. During the period between 5:00 p.m. and 7:00 a.m., the temperature of the house drops and a sufficiently large "thermal mass" is required to keep it from dropping too far. The thermal mass can be a large quantity of stone (with specific heat 850 J/kg C) in the floor and the interior walls exposed to sunlight. What mass of stone is required if the temperature is not to drop below 18.0C overnight?
A certain ideal gas has a molar specific heat of Cv = 72R. A 2.00-mol sample of the gas always starts at pressure 1.00 105 Pa and temperature 300 K. For each of the following processes, determine (a) the final pressure, (b) the final volume, (c) the final temperature, (d) the change in internal energy of the gas, (e) the energy added to the gas by heat, and (f) the work done on the gas. (i) The gas is heated at constant pressure to 400 K. (ii) The gas is heated at constant volume to 400 K. (iii) The gas is compressed at constant temperature to 1.20 105 Pa. (iv) The gas is compressed adiabatically to 1.20 105 Pa.
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.)
On a hot day, the temperature of an 80,000L swimming pool increases by 150C. What is the net heat transfer during this healing? Ignore any complications, such as loss of water by evaporation.