PHYSICS 1250 PACKAGE >CI<
9th Edition
ISBN: 9781305000988
Author: SERWAY
Publisher: CENGAGE LEARNING (CUSTOM)
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Question
Chapter 20, Problem 20.56P
(a)
To determine
The mass of waxy material that is required to perform the bacteriological test.
(b)
To determine
The reason for which the calculation can be done without knowing the mass of test sample.
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Number
Units
A person infected with the SARS-CoV-2 virus is running a fever with an internal body temperature of 103 °F (39.4 °C). This raises the
person's skin temperature to 36.5 °C. The person is standing unclothed in a room with an ambient temperature of 21.0 °C. If the
temperature of the person's skin is maintained at 36.5 °C solely by the energy obtained from the metabolic conversion of food, how
many Calories would this person have to consume per hour? Assume heat is lost only by radiation, and the surface area and emissivity
of the person's skin are 1.50 m2 and 0.800, respectively.
00200
For bacteriological testing of water supplies and in medical clinics, samples must routinely be incubated for 24 h at 37°C. A standard constant - temperature bath with electric heating and thermostatic control is not suitable in developing nations without continuously operating electric power lines. Peace Corps volunteer and MIT engineer Amy Smith invented a low - cost, low-maintenance incubator to fill the need. The device consists of a foam-insulated box containing several packets of a waxy material that melts at 37.0°C, interspersed among tubes, dishes, or bottles containing the test samples and growth medium (food for bacteria). Outside the box, the waxy material is first melted by a stove or solar energy collector. Then it is put into the box to keep the test samples warm as it solidifies. The heat of fusion of the phase-change material is 205 kJ/kg. Model the insulation as a panel with surface area 0.490 m2, thickness 9.50 cm, and conductivity 0.012 0 W/m ∙ °C. Assume the…
Chapter 20 Solutions
PHYSICS 1250 PACKAGE >CI<
Ch. 20 - Prob. 20.1QQCh. 20 - Suppose the same process of adding energy to the...Ch. 20 - Prob. 20.3QQCh. 20 - Characterize the paths in Figure 19.12 as...Ch. 20 - Prob. 20.5QQCh. 20 - An ideal gas is compressed to half its initial...Ch. 20 - A poker is a stiff, nonflammable rod used to push...Ch. 20 - Assume you are measuring the specific heat of a...Ch. 20 - Prob. 20.4OQCh. 20 - Prob. 20.5OQ
Ch. 20 - Ethyl alcohol has about one-half the specific heat...Ch. 20 - The specific heat of substance A is greater than...Ch. 20 - Beryllium has roughly one-half the specific heat...Ch. 20 - Prob. 20.9OQCh. 20 - A 100-g piece of copper, initially at 95.0C, is...Ch. 20 - Prob. 20.11OQCh. 20 - If a gas is compressed isothermally, which of the...Ch. 20 - Prob. 20.13OQCh. 20 - If a gas undergoes an isobaric process, which of...Ch. 20 - Prob. 20.15OQCh. 20 - Prob. 20.1CQCh. 20 - You need to pick up a very hot cooking pot in your...Ch. 20 - Prob. 20.3CQCh. 20 - Prob. 20.4CQCh. 20 - Prob. 20.5CQCh. 20 - In 1801, Humphry Davy rubbed together pieces of...Ch. 20 - Prob. 20.7CQCh. 20 - Prob. 20.8CQCh. 20 - Prob. 20.9CQCh. 20 - When camping in a canyon on a still night, a...Ch. 20 - Pioneers stored fruits and vegetables in...Ch. 20 - Prob. 20.12CQCh. 20 - Prob. 20.1PCh. 20 - Consider Joules apparatus described in Figure...Ch. 20 - Prob. 20.3PCh. 20 - The highest waterfall in the world is the Salto...Ch. 20 - What mass of water at 25.0C must be allowed to...Ch. 20 - The temperature of a silver bar rises by 10.0C...Ch. 20 - In cold climates, including the northern United...Ch. 20 - A 50.0-g sample of copper is at 25.0C. If 1 200 J...Ch. 20 - An aluminum cup of mass 200 g contains 800 g of...Ch. 20 - If water with a mass mk at temperature Tk is...Ch. 20 - A 1.50-kg iron horseshoe initially at 600C is...Ch. 20 - An electric drill with a steel drill bit of mass m...Ch. 20 - An aluminum calorimeter with a mass of 100 g...Ch. 20 - A 3.00-g copper coin at 25.0C drops 50.0 m to the...Ch. 20 - Two thermally insulated vessels are connected by a...Ch. 20 - A 50.0-g copper calorimeter contains 250 g of...Ch. 20 - Prob. 20.17PCh. 20 - How much energy is required to change a 40.0-g ice...Ch. 20 - A 75.0-g ice cube at 0C is placed in 825 g of...Ch. 20 - A 3.00-g lead bullet at 30.0C is fired at a speed...Ch. 20 - Steam at 100C is added to ice at 0C. (a) Find the...Ch. 20 - A 1.00-kg Mock of copper at 20.0C is dropped into...Ch. 20 - In an insulated vessel, 250 g of ice at 0C is...Ch. 20 - Prob. 20.24PCh. 20 - An ideal gas is enclosed in a cylinder with a...Ch. 20 - Prob. 20.26PCh. 20 - One mole of an ideal gas is warmed slowly so that...Ch. 20 - (a) Determine the work done on a gas that expands...Ch. 20 - An ideal gas is taken through a quasi-static...Ch. 20 - A gas is taken through the cyclic process...Ch. 20 - Consider the cyclic process depicted in Figure...Ch. 20 - Why is the following situation impossible? An...Ch. 20 - A thermodynamic system undergoes a process in...Ch. 20 - A sample of an ideal gas goes through the process...Ch. 20 - A 2.00-mol sample of helium gas initially at 300...Ch. 20 - (a) How much work is done on the steam when 1.00...Ch. 20 - Prob. 20.37PCh. 20 - One mole of an ideal gas does 3 000 J of work on...Ch. 20 - A 1.00-kg block of aluminum is warmed at...Ch. 20 - In Figure P19.22, the change in internal energy of...Ch. 20 - An ideal gas initially at Pi, Vi, and Ti is taken...Ch. 20 - An ideal gas initially at Pi, Vi, and Ti is taken...Ch. 20 - A glass windowpane in a home is 0.620 cm thick and...Ch. 20 - A concrete slab is 12.0 cm thick and has an area...Ch. 20 - A student is trying to decide what to wear. His...Ch. 20 - The surface of the Sun has a temperature of about...Ch. 20 - The tungsten filament of a certain 100-W lightbulb...Ch. 20 - At high noon, the Sun delivers 1 000 W to each...Ch. 20 - Two lightbulbs have cylindrical filaments much...Ch. 20 - Prob. 20.50PCh. 20 - A copper rod and an aluminum rod of equal diameter...Ch. 20 - A box with a total surface area of 1.20 m2 and a...Ch. 20 - (a) Calculate the R-value of a thermal window made...Ch. 20 - At our distance from the Sun, the intensity of...Ch. 20 - A bar of gold (Au) is in thermal contact with a...Ch. 20 - Prob. 20.56PCh. 20 - Prob. 20.57PCh. 20 - A gas expands from I to Fin Figure P20.58 (page...Ch. 20 - Gas in a container is at a pressure of 1.50 atm...Ch. 20 - Liquid nitrogen has a boiling point of 77.3 K and...Ch. 20 - An aluminum rod 0.500 m in length and with a cross...Ch. 20 - Prob. 20.62APCh. 20 - Prob. 20.63APCh. 20 - Prob. 20.64APCh. 20 - Prob. 20.65APCh. 20 - An ice-cube tray is filled with 75.0 g of water....Ch. 20 - On a cold winter day. you buy roasted chestnuts...Ch. 20 - Prob. 20.68APCh. 20 - An iron plate is held against an iron wheel so...Ch. 20 - Prob. 20.70APCh. 20 - A 40.0-g ice cube floats in 200 g of water in a...Ch. 20 - One mole of an ideal gas is contained in a...Ch. 20 - Review. A 670-kg meteoroid happens to be composed...Ch. 20 - Prob. 20.74APCh. 20 - Prob. 20.75APCh. 20 - Prob. 20.76APCh. 20 - Water in an electric teakettle is boiling. The...Ch. 20 - Prob. 20.78APCh. 20 - Prob. 20.79APCh. 20 - A student measures the following data in a...Ch. 20 - Consider the piston cylinder apparatus shown in...Ch. 20 - A spherical shell has inner radius 3.00 cm and...Ch. 20 - Prob. 20.83CPCh. 20 - (a) The inside of a hollow cylinder is maintained...
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