Temperature: Is that property of a system which equals that of another system when the two system are in thermal equilibrium. Or Is the physical property of a system which underlies the common notions of”hot” and “cold”; the material with the higher temperature is said to be hotter. Temperature profile of the vertical structure of the Atmosphere. Pressure variation with the Altitude Temperature Scales: T (Kelvin scale) average K.E. Temperature is a measure of the average kinetic energy of the particles in a system What is ?
Thermal Expansion : LL0TLL0T T=T f -T 0 L= L 0 T Const.=Coefficient of linear expansion ( ) L=Const.L 0 T = L /L 0 T (1/ 0 C) Is the increase in each unit length per each unit temperature change. The ball will not pass through The ring until the ring is hotter Than the ball. Different metal expand at different rates when heated. Lakes freeze from the top The comfort zone Liquid Expansion: Air cools faster than the water does. The ice is less dense than liquid water
Gas Expansion: V T (fixed P)V 1/P (fixed T) PV=const.T Ideal gas law The First law of thermodynamics: Conservation of Energy Two means to increase the temperature: heat and work done Internal Energy: The sum of the kinetic energies and potential energies of all the atoms and molecules in a substance.U Since T KE: Temperature is directly proportional to U Heat: The form of energy that is transferred between two substance because of their temperature difference.Q (it is not property of a system like U) 1Cal=4.18J Two objects with the same temperature do not Always feel as hold or as cold as one another.
Specific Heat Capacity: The amount of heat required to increase the unit mass of a certain substance by unit temperature. Q m (fixed T)Q T (fixed m)Q=Const.m T Depends on the kind of the material Q=mc T C=Q/m T (j/kg 0 C) A 50 g sample of copper is at 25 0 C. If 1,200J of energy is added to the copper By heat, what is the final temperature? Imagine you have 1Kg each of iron, glass, and water, and that all of the samples are at 10 0 C.Rank the samples from lowest to highest temperature after 100J is added to each by heat. Calorie: the energy necessary to raise the temperature of 1gm of Water from C to C. U=Q + work 1 St law of thermodynamics A thermodynamic system undergoes a process in which its internal energy decreases by 500J. If at the same time 220J of work is done on the system. Find the energy transferred to or from it by heat? W<0W>0 W<0W>0
An object of mass 6.5kg falls through a height of 50.0m and, by means of a mechanical linkage, rotate a paddle wheel that stirs 520g of water. The Water is initially at 15 0 C. What is the maximum possible temperature rise? Heat Transfer: Conduction ConvectionRadiation Net transfer of energy due to vibrational motions of atoms, molecules without a net Flow of the material. Heat transfer by macroscopic movement of matter Electromagnetic Radiation Phase transition:
Relative humidity=(humidity/saturation density) 100% Relative Humidity: Humidity: The density of water vapor in the air =(Actual vapor density/saturation vapor density) 100% Evaporation process is a cooling process High KE Molecules Temp. decreases What is the relative humidity when the humidity is 0.009kg/m 3 and the temperature is 20 0 C? Saturation density is kg/m 3 at 200C The Second law of thermodynamics: HotCold dQ Preferred direction to the “arrow of time” Heat engine is a device for converting heat into useful work Heat engine Heat movers Efficiency=(energy or work output/energy or work input) 100% Efficiency=(work/Q h ) 100% Heat engine Maximum Efficiency Carnot efficiency=(T h -T L /T h ) 100% Temperature must be in Kelvin No device can be built that will repeatedly extract heat from a source and deliver mechanical work or energy without ejecting some heat to a lower-temperature reservoir. Entropy: is a measure of the amount of disorder in a system
Thank You No more fluid