Objects A and B have the same mass of 3.1 kg and are at their melting points. They melt when 3.8 x 104 J of heat is added to A and when 9.6 x 104 J is added to B. (a), (b) Determine the latent heat of fusion for the substance from which each object is made. (c) Find the heat required to melt object A when its mass is 6.2 kg. (a) LEA (b) L+B= i (c) Q = i

Objects A and B have the same mass of 3.1 kg and are at their melting points. They melt when 3.8 x 104 J of heat is added to A and when 9.6 x 104 J is added to B. (a), (b) Determine the latent heat of fusion for the substance from which each object is made. (c) Find the heat required to melt object A when its mass is 6.2 kg. (a) LEA (b) L+B= i (c) Q = i

Principles of Physics: A Calculus-Based Text

5th Edition

ISBN:9781133104261

Author:Raymond A. Serway, John W. Jewett

Publisher:Raymond A. Serway, John W. Jewett

Chapter17: Energy In Thermal Processes: The First Law Of Thermodynamics

Section: Chapter Questions

Problem 4OQ

See similar textbooks

Similar questions

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.
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.
Consider the latent heat of fusion and the latent heat of vaporization for H2O, 3.33 105 J/kg and 2.256 106 J/kg, respectively. How much heat is needed to a. melt 2.00 kg of ice and b. vaporize 2.00 kg of water? Assume the temperatures of the ice and steam are at the melting point and vaporization point, respectively. (a). UsingEq21.9, Q = mLF = (2.00 kg) (3.33l05 J/kg) = 6.66105 J (b).UsingEq21.10. Q = mLV = (2.00kg) (2.256106 J/kg) = 14.51106 J
At 25.0 m below the surface of the sea, where the temperature is 5.00C, a diver exhales an air bubble having a volume of 1.00 cm3. If the surface temperature of the sea is 20.0C, what is the volume of the bubble just before it breaks the surface?
In an air conditioner, 12.65 MJ of heat transfer occurs from a cold environment in 1.00 h. (a) What mass of ice melting would involve the same heat transfer? (b) How many hours of operation would be equivalent to melting 900 kg ofice? (c) If ice costs 20 cents per kg, do you think the air conditioner could be operated more cheaply than by simply using ice? Describe in detail how you evaluate the relative costs.
(a) What is the rate of heat conduction through the 3.00-cm-thick fur of a large animal having a 1.40-m2 surface area? Assume that the animal’s skin temperature is 32.0 °C , that the air temperature is −5.00 °C , and thatfur has the same thermal conductivity as air. (b) What food intake will the animal need in one day to replace this heat transfer?
Objects A and B have the same mass of 3.9 kg and are at their melting points. They melt when 3.2 × 104 J of heat is added to A and when 11 × 104 J is added to B. (a), (b) Determine the latent heat of fusion for the substance from which each object is made. (c) Find the heat required to melt object A when its mass is 7.8 kg.
(a) What is the rate of heat conduction through the 3.00-cm-thick fur of a large animal having a 1.40-m2 surface area? Assume that the animal’s skin temperature is 32.0ºC , that the air temperature is −5.00ºC , and that furhas the same thermal conductivity as air. (b) What food intake will the animal need in one day to replace this heat transfer?
(a) Calculate the rate of heat conduction through house walls that are 13.0 cm thick and that have an average thermal conductivity twice that of glass wool. Assume there are no windows or doors. The surface area of the walls is 120 m2 and their inside surface is at 18.0ºC , while their outside surface is at 5.00ºC . (b) How many 1-kW room heaters would be needed to balance the heat transfer due to conduction?
Tortilla chips are manufactured by submergingbaked and partially cooled masa at 41 °C into corn oil at 182 °C.(a) If the specific heat of masa is 1850 J>1kg # K2, how much thermalenergy is required to warm 0.454 kg of masa to the temperature ofthe oil? (b) If the production line makes 227 kg of chips every hour,at what rate (in kW) must thermal energy be supplied to the cornoil, assuming that all of the energy goes into warming the masa?
A square pane of glass 0.500 m on a side is 6.00 mm thick. Whenthe temperatures on the two sides of the glass are 25.0°C and -10.0°C,the heat current due to conduction through the glass is 1.10 * 10^3 W.(a) What is the thermal conductivity of the glass? (b) If the thickness of theglass is increased to 9.00 mm, what will be the heat current?
Suppose 8.50 x 10° J of energy are transferred to 1.79 kg of ice at 0°C. The latent heat of fusion and specific heat of water are L; = 3.33 x 10° J/kg and c = 4186 (kg · °C) HINT (a) Calculate the energy (in J) required to melt all the ice into liquid water. (Enter your answer to at least three significant figures.) (b) How much energy (in J) remains to raise the temperature of the liquid water? (Enter your answer to at least three significant figures.) (c) Determine the final temperature of the liquid water in Celsius. °C