



This law was postulated in the 1930s, after the first and second laws of thermodynamics had been developed and named. It is called the
zeroth law because it comes logically before the first and second laws (discussed in
Thermodynamics ). An example of this law in action is seen in babies in incubators: babies in incubators normally have very few clothes on, so to an observer they look as if they may not be warm enough. However, the temperature of the air, the cot, and the baby is the same, because they are in thermal equilibrium, which is accomplished by maintaining air temperature to keep the baby comfortable.
Does the temperature of a body depend on its size?
No, the system can be divided into smaller parts each of which is at the same temperature. We say that the temperature is an
intensive quantity. Intensive quantities are independent of size.
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Section summary
 Temperature is the quantity measured by a thermometer.
 Temperature is related to the average kinetic energy of atoms and molecules in a system.
 Absolute zero is the temperature at which there is no molecular motion.
 There are three main temperature scales: Celsius, Fahrenheit, and Kelvin.
 Temperatures on one scale can be converted to temperatures on another scale using the following equations:
${T}_{\text{\xba}\text{F}}=\frac{9}{5}{T}_{\text{\xba}\text{C}}+\text{32}$
${T}_{\text{\xba}\text{C}}=\frac{5}{9}\left({T}_{\text{\xba}\text{F}}\text{32}\right)$
${T}_{\text{K}}={T}_{\text{\xba}\text{C}}+\text{273}\text{.}\text{15}$
${T}_{\text{\xba}\text{C}}={T}_{\text{K}}\text{273}\text{.}\text{15}$
 Systems are in thermal equilibrium when they have the same temperature.
 Thermal equilibrium occurs when two bodies are in contact with each other and can freely exchange energy.
 The zeroth law of thermodynamics states that when two systems, A and B, are in thermal equilibrium with each other, and B is in thermal equilibrium with a third system, C, then A is also in thermal equilibrium with C.
Conceptual questions
If you add boiling water to a cup at room temperature, what would you expect the final equilibrium temperature of the unit to be? You will need to include the surroundings as part of the system. Consider the zeroth law of thermodynamics.
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Problems&Exercises
To conserve energy, room temperatures are kept at
$\text{68}\text{.}0\text{\xba}\text{F}$ in the winter and
$\text{78}\text{.}0\text{\xba}\text{F}$ in the summer. What are these temperatures on the Celsius scale?
$\text{20}\text{.}0\text{\xba}\text{C}$ and
$\text{25}\text{.}6\text{\xba}\text{C}$
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One of the hottest temperatures ever recorded on the surface of Earth was
$\text{134}\text{\xba}\text{F}$ in Death Valley, CA. What is this temperature in Celsius degrees? What is this temperature in Kelvin?
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(a) Suppose a cold front blows into your locale and drops the temperature by 40.0 Fahrenheit degrees. How many degrees Celsius does the temperature decrease when there is a
$\text{40}\text{.}0\text{\xba}\text{F}$ decrease in temperature? (b) Show that any change in temperature in Fahrenheit degrees is ninefifths the change in Celsius degrees.
(a)
$\text{22}\text{.}2\text{\xba}\text{C}$
(b)
$\begin{array}{lll}\text{\Delta}T\left(\text{\xba}\text{F}\right)& =& {T}_{2}\left(\text{\xba}\text{F}\right){T}_{1}\left(\text{\xba}\text{F}\right)\\ & =& \frac{9}{5}{T}_{2}\left(\text{\xba}\text{C}\right)+\text{32}\text{.}0\text{\xba}\left(\frac{9}{5}{T}_{1}\left(\text{\xba}\text{C}\right)+\text{32}\text{.}0\text{\xba}\right)\\ & =& \frac{9}{5}\left({T}_{2}\left(\text{\xba}\text{C}\right){T}_{1}\left(\text{\xba}\text{C}\right)\right)\text{}=\frac{9}{5}\text{\Delta}T\left(\text{\xba}\text{C}\right)\end{array}$
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(a) At what temperature do the Fahrenheit and Celsius scales have the same numerical value? (b) At what temperature do the Fahrenheit and Kelvin scales have the same numerical value?
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Questions & Answers
Calculate the work done by an 85.0kg man who pushes a crate 4.00 m up along a ramp that makes an angle of 20.0º20.0º with the horizontal. (See [link] .) He exerts a force of 500 N on the crate parallel to the ramp and moves at a constant speed. Be certain to include the work he does on the crate an
What is thermal heat all about
why uniform circular motion is called a periodic motion?.
when a train start from A & it returns at same station A . what is its acceleration?
what is distance of A to B of the stations and what is the time taken to reach B from A
BELLO
the information provided is not enough
aliyu
Hmmmm maybe the question is logical
yusuf
where are the parameters for calculation
HENRY
there is enough information to calculate an AVERAGE acceleration
Kwok
mistake, there is enough information to calculate an average velocity
Kwok
what is the unit of momentum
Abel
wha are the types of radioactivity ?
what are the types of radioactivity
Worku
It is the opposite of kinetic friction
Mark
static fiction is friction between two surfaces in contact an none of sliding over on another, while Kinetic friction is friction between sliding surfaces in contact.
MINDERIUM
I don't get it,if it's static then there will be no friction.
author
It means that static friction is that friction that most be overcome before a body can move
kingsley
static friction is a force that keeps an object from moving, and it's the opposite of kinetic friction.
author
It is a force a body must overcome in order for the body to move.
Eboh
If a particle accelerator explodes what happens
Eboh
why we see the edge effect in case of the field lines of capacitor?
Arnab
force is something which is responsible for the object to change its position
MINDERIUM
more technically it is the product of mass of an object and Acceleration produced in it
MINDERIUM
wave is disturbance in any medium
iqra
energy is distributed in any medium through particles of medium.
iqra
If a particle accelerator explodes what happens
we have to first figure out .... wats a particle accelerator first
Teh
The resistive force of surface.
iqra
Who can tutor me on simple harmonic motion
on both a string and peldulum?
Anya
Do you have a chitchat contact
yusuf
I dont have social media but i do have an email?
Anya
Where are you chatting from
yusuf
I don't understand the basics of this group
Jimmy
Simple harmonic motion
yusuf
how.an.equipotential.line is two dimension and equipotential surface is three dimension ?
definition of mass of conversion
Force equals mass time acceleration. Weight is a force and it can replace force in the equation. The acceleration would be gravity, which is an acceleration. To change from weight to mass divide by gravity (9.8 m/s^2).
Marisa
how many subject is in physics
the write question should be " How many Topics are in O Level Physics, or other branches of physics.
effiom
how many topic are in physics
Praise
Praise what level are you
yusuf
If u are doing a levels in your first year you do AS topics therefore you do 5 big topic i.e particles radiation, waves and optics, mechanics,materials, electricity. After that you do A level topics like Specific Harmonic motion circular motion astrophysics depends really
Anya
Yeah basics of physics prin8
yusuf
Heat nd Co for a level
yusuf
yh I need someone to explain something im tryna solve . I'll send the question if u down for it
a ripple tank experiment a vibrating plane is used to generate wrinkles in the water .if the distance between two successive point is 3.5cm and the wave travel a distance of 31.5cm find the frequency of the vibration
Tamdy
please send the answer
Boniface
the range of objects and phenomena studied in physics is
I don't know please give the answer
Boniface
Source:
OpenStax, College physics. OpenStax CNX. Jul 27, 2015 Download for free at http://legacy.cnx.org/content/col11406/1.9
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