lecture 3sirenko/phys-103-2005/lecture7.pdfwater linear expansion coefficient is 69ewater linear...
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Lecture 3
Temperature, Thermal expansion, and Heat
(NJIT Physics, Chapter 10)( y p )
http://web.njit.edu/~sirenko/Phys-103-2005/Phys-103-2012.htm
Physics 103 Spring 2012
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Last Lecture: Bernoulli's Equation
W fl hl h h h i h i h fi d diWater flows smoothly through the pipe shown in the figure, descending in the process. Rank the four numbered sections of pipe according to (a) the volume flow rate RV through them, (b) the flow speed v through V g , ( ) p gthem, and (c) the water pressure p within them, greatest first.
a) all tie; b) 1, then 2 and 3 tie, 4 (wider means slower);
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c) (c) 4, 3, 2, 1 (wider and lower mean more pressure)
What is Temperature anyway ?
Temperature is one of the basic SI quantities.Cannot be expressed through kg-m-s
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Cannot be expressed through kg m s
Temperature in C and F
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T=0 what is that?
P
TT 273 15 C TT=0 KT=-273.15 C
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Zero’th law of Thermodynamics
If bodies A and B are each in thermal equilibrium with a hi d b d h h ithird body T, then they are in
thermal equilibrium with each other
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Temperature difference determines the Heat transfer processthe Heat transfer process
What is the direction for the heat transfer Between a,b,c,d?
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Temperature difference determines the Heat transfer processthe Heat transfer process
What is the direction for the heat transfer Between a,b,c,d?
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Zero’th law of Thermodynamics
If bodies A and B are each in thermal equilibrium with a hi d b d h h ithird body T, then they are in
thermal equilibrium with each other
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Pressure, Temperature, and Speed of moleculesSpeed of molecules
3RTv =
mN is the molar mass M
rmsvM
=
Root-mean-square speedmNA is the molar mass M
21 2
2
1
21 3
avg avg
B
K mv T
K mv k T
=
= =
∼
2 2Boltzman Constant
avg avg B
B
K mv k T
k −
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The Distribution of Molecular Speeds
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Linear thermal expansion
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2D and 3D expansion
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Thermal expansion (continued)
Why days are longer During the Summer time?During the Summer time?
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Thermal expansion (atomic model)
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Thermal expansion
What is the ocean level increase due to +1 C◦ global warming ?
Water linear expansion coefficient is 69e 6/C◦ at 20 C◦Water linear expansion coefficient is ~69e-6/C at 20 C◦.
Average ocean depth is 4 km
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Properties of Water (H2O)
negative thermal expansion of water between 0 and 4 C
Freezes at 0 C boils at 100 C
negative thermal expansion i Z W O
Freezes at 0 C, boils at 100 C
in ZrW2O8
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The Triple Point of Water
A triple-point cell, in which solid ice, liquid water, and
t i t i th lwater vapor coexist in thermal equilibrium. By international agreement, the temperature of this mixture has been defined to be 273.16 K. The bulb of a constant-volume gasconstant volume gas thermometer is shown inserted into the well of the cell.
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Thermal Expansion: QZ#2
When is the Empire State building taller?
A. On MondaysB. During rush hourB. During rush hourC. On a sunny Summer dayD. During Moon eclipseE. Valentines Day
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