University Physics with Modern Physics, Volume 1 (Chs. 1-20) and Mastering Physics with Pearson eText & ValuePack Access Card (14th Edition)
14th Edition
ISBN: 9780134209586
Author: Hugh D. Young
Publisher: PEARSON
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Textbook Question
Chapter 17, Problem 17.87P
Hot Air in a Physics Lecture. (a) A typical student listening attentively to a physics lecture has a heat output of 100 W. How much heat energy does a class of 140 physics students release into a lecture hall over the course of a 50-min lecture? (b) Assume that all the heat energy in part (a) is transferred to the 3200 m3 of air in the room. The air has specific heat 1020J/kg·K and density 1.20 kg/m3. If none of the heat escapes and the air conditioning system is off, how much will the temperature of the air in the room rise during the 50-min lecture? (c) If the class is taking an exam, the heat output per student rises to 280 W. What is the temperature rise during 50 min in this case?
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Students have asked these similar questions
a) A typical student listening
attentively to a physics lecture has
a heat output of 108 W. How
much heat energy does a class of
95 physics students release into a
lecture hall over the course of a
50 min lecture? Express your
answer in joules.
b) Assume that all the heat energy
in part A is transferred to the 3204
m3 of air in the room. The air has
a specific heat of 1020 J/(kg.K)
and a density of 1.20 kg/m3. If
none of the heat escapes and the
air-conditioning system is off, how
much will the temperature of the
air in the room rise during the 50
min lecture? Express your answer
in Celsius degrees.
c) If the class is taking an exam,
the heat output per student rises
to 285 W. What is the temperature
rise during 50 min in this case?
Express your answer in Celsius
degrees.
A classroom has dimensions 8.00 m x 10.00 m x 3.00 m. A 1000 W electric space
heater is being used to warm the room from 5.00°C to 20.00°C on a cold morning. If
the density of air is 1.29 kg/m°, and the specific heat capacity of air is 1004 J/(kg-K),
how long will it take to heat the room? Assume no loss of thermal energy to the
surroundings.
A) 1.30 minutes
B) 241 minutes
C) 45.3 minutes
O D) 77.7 minutes
Geologists measure conductive heat flow out of the earth by drilling holes (a few hundred meters deep) and measuring the temperature as a function of depth. Suppose that in a certain location the temperature increases by 20°C per kilometer of depth and the thermal conductivity of the rock is 2.5 W/m·K. What is the rate of heat conduction per square meter in this location? Assuming that this value is typical of other locations over all of earth's surface, at approximately what rate is the earth losing heat via conduction? (The radius of the earth is 6400 km.)
Chapter 17 Solutions
University Physics with Modern Physics, Volume 1 (Chs. 1-20) and Mastering Physics with Pearson eText & ValuePack Access Card (14th Edition)
Ch. 17.1 - You put a thermometer in a pot of hot water and...Ch. 17.2 - Which of the following types of thermometers have...Ch. 17.3 - Prob. 17.3TYUCh. 17.4 - In the bimetallic strip shown in Fig. 17.3a, metal...Ch. 17.5 - Prob. 17.5TYUCh. 17.6 - You take a block of ice at 0C and add heat to it...Ch. 17.7 - A room has one wall made of concrete, one wall...Ch. 17 - Explain why it would not make sense to use a...Ch. 17 - If you heat the air inside a rigid, scaled...Ch. 17 - Many automobile engines have cast-iron cylinders...
Ch. 17 - Why do frozen water pipes burst? Would a mercury...Ch. 17 - Two bodies made of the same material have the same...Ch. 17 - Why is it sometimes possible to loosen caps on...Ch. 17 - The inside of an oven is at a temperature of 200C...Ch. 17 - A newspaper article about the weather states that...Ch. 17 - A student asserts that a suitable unit for...Ch. 17 - Prob. 17.10DQCh. 17 - The units of specific heat c are J/kg K, but the...Ch. 17 - Why is a hot, humid day in the tropics generally...Ch. 17 - A piece of aluminum foil used to wrap a potato for...Ch. 17 - Desert travelers sometimes keep water in a canvas...Ch. 17 - When you first step out of the shower, you feel...Ch. 17 - The climate of regions adjacent to large bodies of...Ch. 17 - When water is placed in ice-cube trays in a...Ch. 17 - Before giving you an injection, a physician swabs...Ch. 17 - A cold block of metal feels colder than a block of...Ch. 17 - A person pours a cup of hot coffee, intending to...Ch. 17 - When a freshly baked apple pie has just been...Ch. 17 - Old-time kitchen lore suggests that things cook...Ch. 17 - In coastal regions in the winter, the temperature...Ch. 17 - It is well known that a potato bakes faster if a...Ch. 17 - Glider pilots in the Midwest know that thermal...Ch. 17 - Some folks claim that ice cubes freeze faster if...Ch. 17 - Were lucky that the earth isnt in thermal...Ch. 17 - Prob. 17.28DQCh. 17 - Convert the following Celsius temperatures to...Ch. 17 - BIO Temperatures in Biomedicine. (a) Normal body...Ch. 17 - Prob. 17.3ECh. 17 - (a) Calculate the one temperature at which...Ch. 17 - You put a bottle of soft drink in a refrigerator...Ch. 17 - Prob. 17.6ECh. 17 - The pressure of a gas at the triple point of water...Ch. 17 - Prob. 17.8ECh. 17 - Prob. 17.9ECh. 17 - Prob. 17.10ECh. 17 - The Humber Bridge in England has the worlds...Ch. 17 - One of the tallest buildings in the world is the...Ch. 17 - A U.S. penny has a diameter of 1.9000 cm at 20.0C....Ch. 17 - Ensuring a Tight Fit. Aluminum rivets used in...Ch. 17 - A copper cylinder is initially at 20.0C. At what...Ch. 17 - A geodesic dome constructed with an aluminum...Ch. 17 - A glass flask whose volume is 1000.00 cm3 at 0.0C...Ch. 17 - A steel tank is completely filled with 1.90 m3 of...Ch. 17 - A machinist bores a hole of diameter 1.35 cm in a...Ch. 17 - As a new mechanical engineer for Engines Inc., you...Ch. 17 - Steel train rails are laid in 12.0-m-long segments...Ch. 17 - A brass rod is 185 cm long and 1.60 cm in...Ch. 17 - An aluminum tea kettle with mass 1.10 kg and...Ch. 17 - In an effort to stay awake for an all-night study...Ch. 17 - Prob. 17.25ECh. 17 - BIO Heat Loss During Breathing. In very cold...Ch. 17 - You are given a sample of metal and asked to...Ch. 17 - On-Demand Water Heaters. Conventional hot-water...Ch. 17 - Prob. 17.29ECh. 17 - Prob. 17.30ECh. 17 - CP A nail driven into a board increases in...Ch. 17 - A technician measures the specific heat of an...Ch. 17 - CP A 15.0-g bullet traveling horizontally at 865...Ch. 17 - You have 750 g of water at 10.0C in a large...Ch. 17 - Prob. 17.35ECh. 17 - BIO Treatment for a Stroke. One suggested...Ch. 17 - A blacksmith cools a 1.20-kg chunk of iron,...Ch. 17 - A copper calorimeter can with mass 0.100 kg...Ch. 17 - A copper pot with a mass of 0.500 kg contains...Ch. 17 - In a container of negligible mass, 0.200 kg of ice...Ch. 17 - Prob. 17.41ECh. 17 - BIO Before going in for his annual physical, a...Ch. 17 - Prob. 17.43ECh. 17 - Prob. 17.44ECh. 17 - How much heat is required to convert 18.0 g of ice...Ch. 17 - An open container holds 0.550 kg of ice at 15.0C....Ch. 17 - CP What must the initial speed of a lead bullet be...Ch. 17 - BIO Steam Burns Versus Water Burns. What is the...Ch. 17 - BIO The Ship of the Desert. Camels require very...Ch. 17 - BIO Evaporation of sweat is an important mechanism...Ch. 17 - CP An asteroid with a diameter of 10 km and a mass...Ch. 17 - A laboratory technician drops a 0.0850-kg sample...Ch. 17 - An insulated beaker with negligible mass contains...Ch. 17 - A 4.00-kg silver ingot is taken from a furnace,...Ch. 17 - A vessel whose walls are thermally insulated...Ch. 17 - Prob. 17.56ECh. 17 - Suppose that the rod in Fig. 17.24a is made of...Ch. 17 - One end of an insulated metal rod is maintained at...Ch. 17 - A carpenter builds an exterior house wall with a...Ch. 17 - An electric kitchen range has a total wall area of...Ch. 17 - BIO Conduction Through the Skin. The blood plays...Ch. 17 - A long rod, insulated to prevent heat loss along...Ch. 17 - A pot with a steel bottom 8.50 mm thick rests on a...Ch. 17 - You are asked to design a cylindrical steel rod...Ch. 17 - A picture window has dimensions of 1.40 m 2.50 m...Ch. 17 - Prob. 17.66ECh. 17 - A spherical pot contains 0.75 L of hot coffee...Ch. 17 - The emissivity of tungsten is 0.350. A tungsten...Ch. 17 - Size of a Light-Bulb Filament. The operating...Ch. 17 - The Sizes of Stars. The hot glowing surfaces of...Ch. 17 - CP A Foucault pendulum consists of a brass sphere...Ch. 17 - Suppose that a steel hoop could be constructed to...Ch. 17 - You propose a new temperature scale with...Ch. 17 - CP CALC A 250-kg weight is hanging from the...Ch. 17 - Prob. 17.75PCh. 17 - A surveyors 30.0-m steel tape is correct at 20.0C....Ch. 17 - A metal rod that is 30.0 cm long expands by 0.0650...Ch. 17 - On a cool (4.0C) Saturday morning, a pilot fills...Ch. 17 - (a) Equation (17.12) gives the stress required to...Ch. 17 - CP A metal wire, with density and Youngs modulus...Ch. 17 - A steel ring with a 2.5000-in. inside diameter at...Ch. 17 - BIO Doughnuts: Breakfast of Champions! Atypical...Ch. 17 - BIO Shivering. Shivering is your bodys way of...Ch. 17 - You cool a 100.0-g slug of red-hot iron...Ch. 17 - CALC Debyes T3 Law. At very low temperatures the...Ch. 17 - CP A person of mass 70.0 kg is sitting in the...Ch. 17 - Hot Air in a Physics Lecture. (a) A typical...Ch. 17 - CALC The molar heat capacity of a certain...Ch. 17 - Prob. 17.89PCh. 17 - BIO Overheating. (a) By how much would the body...Ch. 17 - BIO A Thermodynamic Process in an Insect. The...Ch. 17 - Hot Water Versus Steam Heating. In a household...Ch. 17 - You have 1.50 kg of water at 28.0C in an insulated...Ch. 17 - A thirsty nurse cools a 2.00-L bottle of a soft...Ch. 17 - Prob. 17.95PCh. 17 - A Styrofoam bucket of negligible mass contains...Ch. 17 - In a container of negligible mass, 0.0400 kg of...Ch. 17 - Prob. 17.98PCh. 17 - Effect of a Window in a Door. A carpenter builds a...Ch. 17 - One experimental method of measuring an insulating...Ch. 17 - Compute the ratio of the rate of heat loss through...Ch. 17 - Rods of copper, brass, and steeleach with...Ch. 17 - A brass rod 12.0 cm long, a copper rod 18.0 cm...Ch. 17 - BIO Basal Metabolic Rate. The basal metabolic rate...Ch. 17 - Prob. 17.105PCh. 17 - Prob. 17.106PCh. 17 - A Thermos for Liquid Helium. A physicist uses a...Ch. 17 - A metal sphere with radius 3.20 cm is suspended in...Ch. 17 - Prob. 17.109PCh. 17 - The icecaps of Greenland and Antarctica contain...Ch. 17 - DATA As a physicist, yon put heat into a 500.0-g...Ch. 17 - DATA At a chemical plant where you are an...Ch. 17 - DATA During your mechanical engineering...Ch. 17 - Prob. 17.114CPCh. 17 - A hollow cylinder has length L, inner radius a,...Ch. 17 - You place 35 g of this cryoprotectant at 22C in...Ch. 17 - Careful measurements show that the specific heat...Ch. 17 - In another experiment, you place a layer of this...Ch. 17 - To measure the specific heat in the liquid phase...
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