PHYSICS FOR SCI.AND ENGR W/WEBASSIGN
10th Edition
ISBN: 9781337888462
Author: SERWAY
Publisher: CENGAGE L
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Question
Chapter 19, Problem 28P
(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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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 19 Solutions
PHYSICS FOR SCI.AND ENGR W/WEBASSIGN
Ch. 19.2 - Prob. 19.1QQCh. 19.3 - Suppose the same process of adding energy to the...Ch. 19.5 - Prob. 19.3QQCh. 19.5 - Characterize the paths in Figure 19.12 as...Ch. 19.6 - Prob. 19.5QQCh. 19 - Prob. 1PCh. 19 - The highest waterfall in the world is the Salto...Ch. 19 - Prob. 3PCh. 19 - The temperature of a silver bar rises by 10.0C...Ch. 19 - You are working in your kitchen preparing lunch...
Ch. 19 - If water with a mass mk at temperature Tk is...Ch. 19 - An aluminum calorimeter with a mass of 100 g...Ch. 19 - An electric drill with a steel drill bit of mass m...Ch. 19 - A 3.00-g copper coin at 25.0C drops 50.0 m to the...Ch. 19 - How much energy is required to change a 40.0-g ice...Ch. 19 - Prob. 11PCh. 19 - A 3.00-g lead bullet at 30.0C is fired at a speed...Ch. 19 - In an insulated vessel, 250 g of ice at 0C is...Ch. 19 - Prob. 14PCh. 19 - One mole of an ideal gas is warmed slowly so that...Ch. 19 - (a) Determine the work done on a gas that expands...Ch. 19 - A thermodynamic system undergoes a process in...Ch. 19 - Why is the following situation impossible? An...Ch. 19 - A 2.00-mol sample of helium gas initially at 300...Ch. 19 - (a) How much work is done on the steam when 1.00...Ch. 19 - A 1.00-kg block of aluminum is warmed at...Ch. 19 - In Figure P19.22, the change in internal energy of...Ch. 19 - A student is trying to decide what to wear. His...Ch. 19 - A concrete slab is 12.0 cm thick and has an area...Ch. 19 - Two lightbulbs have cylindrical filaments much...Ch. 19 - Prob. 26PCh. 19 - (a) Calculate the R-value of a thermal window made...Ch. 19 - Prob. 28PCh. 19 - Gas in a container is at a pressure of 1.50 atm...Ch. 19 - Prob. 30APCh. 19 - You have a particular interest in automobile...Ch. 19 - You are working in a condensed-matter laboratory...Ch. 19 - Prob. 33APCh. 19 - Prob. 34APCh. 19 - Prob. 35APCh. 19 - Prob. 36APCh. 19 - An ice-cube tray is filled with 75.0 g of water....Ch. 19 - Prob. 38APCh. 19 - An iron plate is held against an iron wheel so...Ch. 19 - One mole of an ideal gas is contained in a...Ch. 19 - Prob. 41APCh. 19 - Prob. 42APCh. 19 - Prob. 43APCh. 19 - A student measures the following data in a...Ch. 19 - (a) The inside of a hollow cylinder is maintained...Ch. 19 - A spherical shell has inner radius 3.00 cm and...Ch. 19 - Prob. 47CP
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