Faculty of Natural Sciences Depart of Math PHYs amp Stats PHY 110 Physics FOR ENGINEERS Lecture 4 THURSDAY SEPT 15 2011 1 Lecture Notes For this information visit my website ID: 497957
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University of GuyanaFaculty of Natural SciencesDepart. of Math, PHYs & StatsPHY 110 – Physics FOR ENGINEERSLecture 4(THURSDAY, SEPT. 15, 2011)
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Lecture Notes: For this information, visit my website:http://ugphysics.weebly.com2Slide3
Assessments: Group Assignment # 1 due on Friday September 23, 2011. Power Point Presentations1.8_Radiation.1.9_First Law of Thermodynamics. Heat & Work.
NB: The written report is due before the oral presentation is done. Its main content is at least five (5) pages in length, double spacing.
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Assessments Cont’d:Tutorial Groups are Assignment Groups:Mondays – 12:15 p.m. (Mechanical Eng.)Tuesday s– 10:15 a.m. (Civil Eng.) Tuesdays – 2:15 p.m. (Civil Eng.)
Wednesdays – 2:15 p.m. (Civil Eng.)Thursdays – 2:15 p.m. (Civil Eng.)
NB:
Groups 1 & 2 are presenting on Friday September 23, 2011.
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Assessments: Individual Assignment: 1st Oral Quizz on Friday September 30, 2011.Heat – 2.5 %NB:
This will be conducted in my office (Room E 18). Students will indicate a topic of their choice which they would be quizzed on.
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Assessments Cont’d:Tutorial Groups are Assignment Groups:Mondays – 12:15 p.m. (Mechanical Eng.)Tuesday s– 10:15 a.m. (Civil Eng.) Tuesdays – 2:15 p.m. (Civil Eng.)
Wednesdays – 2:15 p.m. (Civil Eng.)
Thursdays – 2:15 p.m. (Civil Eng.)
NB:
Groups 3 to 5 would be quizzed on Friday September 30, 2011.
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Assessments Cont’d:Tutorial Groups are Assignment Groups:Mondays – 12:15 p.m. (Mechanical Eng.)Tuesday s– 10:15 a.m. (Civil Eng.) Tuesdays – 2:15 p.m. (Civil Eng.)
Wednesdays – 2:15 p.m. (Civil Eng.)Thursdays – 2:15 p.m. (Civil Eng.)
NB:
Groups 1 to 2 would be quizzed on Friday October 7, 2011.
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1.5 The Gas Laws8Introduction: The experimental relationships between the pressures, volumes and temperatures of gases were investigated by various workers in the 17th and 18th centuries. These early experiments resulted in three laws – the so-called gas laws.
(A-Level Physics by Roger
Muncaster
, 4
th
Ed. Pg 249)Slide9
1.5 The Gas Laws9Boyle’s Law: For a fixed mass of gas at constant temperature, the product of pressure and volume is a constantCharles’ Law: For a fixed mass of gas at constant pressure, the volume is directly proportional to the temperature measured in Kelvin.
Pressure Law: For a fixed mass of gas at constant volume, the pressure is directly proportional to the temperature measured in Kelvin.
(A-Level Physics by Roger
Muncaster
, 4
th
Ed, pg 249)Slide10
1.5 The Gas Laws10 Kinetic Theory of Matter:Physics for the IB Diploma by Tim Kirk, pg 24.Slide11
1.5 The Gas Laws11 Kinetic Theory of Matter: Solids
Physics for the IB Diploma by Tim Kirk, pg 24.Slide12
1.5 The Gas Laws12 Kinetic Theory of Matter: LiquidsPhysics for the IB Diploma by Tim Kirk, pg 24.Slide13
1.5 The Gas Laws13 Kinetic Theory of Matter: Gases
Physics for the IB Diploma by Tim Kirk, pg 24.Slide14
1.5 The Gas Laws14Kinetic Theory of Gases:Assumptions:Newtonian Mechanics applicable to molecules.No intermolecular forces present. Molecules are perfectly spherical (point objects).
Infinitesimal size of molecules (no volume).
Molecules in Random motion.
Molecular collisions are elastic (K.E. Conserved).
Duration of molecular collisions is negligible.
Taken from Physics for the IB Diploma by Tim Kirk, pg 29.Slide15
1.5 The Gas Laws15Boyle’s Law: For a fixed mass of gas at constant temperature, the pressure of a gas is inversely proportional to its volume.
Robert Boyle:
Considered a founder of the scientific method, 17th-century English scientist Robert Boyle believed in the importance of objective observation and controlled experimentation. He separated chemistry from alchemy and was the first to isolate and study a gas.
Microsoft ® Encarta ® 2007Slide16
1.5 The Gas Laws16Experimental Verification of Boyle’s Law:
(A-Level Physics by Roger
Muncaster
, 4
th
Ed. Pg 259)Slide17
1.5 The Gas Laws17Experimental Verification of Boyle’s Law Cont’d:Slide18
1.5 The Gas Laws18Charles’ Law: For a fixed mass of gas at constant pressure, the volume is directly proportional to the temperature measured in Kelvin.
Jacques Charles (1746-1823),
French chemist, physicist, and aeronaut. Jacques
Alexandre
César Charles was born in
Beaugency
,
Loiret
. In 1783 he made the first balloon using hydrogen gas and ascended to a height of nearly 3 km (2 mi). In 1787 he discovered the relationship between the volume of gas and temperature, known variously as Gay-Lussac's law or Charles's law. He was elected to the French Academy in 1785.
Microsoft ® Encarta ® 2007. Slide19
1.5 The Gas Laws19Experimental Verification of Charles Law:
(A-Level Physics by Roger
Muncaster
, 4
th
Ed. Pg 259)Slide20
2.4 The Gas Laws20Experimental Verification of Charles Law Cont’d:
(A-Level Physics by Roger
Muncaster
, 4
th
Ed. Pg 259)Slide21
1.5 The Gas Laws21Comparison of Boyle’s Law and Charles Law:Slide22
1.5 The Gas Laws22Pressure Law: For a fixed mass of gas at constant volume, the pressure is directly proportional to the temperature measured in Kelvin.NB: The Pressure Law may be derived from the previous two laws.Slide23
1.5 The Gas Laws23Experimental Verification of Pressure Law:
(A-Level Physics by Roger Muncaster, 4th Ed. Pg 260-1)Slide24
1.5 The Gas Laws24Experimental Verification of Pressure Law Cont’d:
(A-Level Physics by Roger Muncaster, 4th Ed. Pg 260-1)zSlide25
1.5 The Gas Laws25Ideal Gas Equation: In this equation, n represents the number of moles of a gas. The constant R on the right-hand side of the equation is a universal constant and has a value of 8.31447 J/mol·K. This single equation can predict the behavior of a gas even if multiple conditions are changed simultaneously. If both the pressure and volume of a gas double, for example, its temperature will increase by a factor of four.
Microsoft ® Encarta ® 2007Slide26
1.5 The Gas Laws26Ideal Gas Equation: This is often referred to as an equation of state. It is employed to predict the behaviour of a system. System:
This is a region of space set aside for scientific investigation. The parameters pressure, volume and temperature gives quantitative description of this system and are deemed as thermodynamic quantities. Thus the ideal gas equation gives the relationship between pressure, volume and temperature of a gas.Slide27
1.5 The Gas Laws27Ideal Gas Equation Cont’d: By combining the three gas laws results: Boyle’s Law:Charles’ Law:
Pressure Law:The three quantities are thus related:Slide28
1.5 The Gas Laws28Ideal Gas Equation Cont’d: Introducing a constant of proportionality results:
Thus the ideal gas equation gives the relationship between pressure, volume and temperature of a gas.Slide29
1.5 The Gas Laws29Ideal Gas Equation Cont’d: Where:P – Pressure of a gas in Pa (Nm
-2).V – Volume occupied by the gas in m
3
.
T
– Thermodynamic temperature of a gas in K.
n
– Number of moles of a gas in mol.
R
– Universal gas constant = 8.314 J mol
-1
K
-1
.Slide30
Lecture Notes: For this information, visit my website:http://ugphysics.weebly.com30Slide31
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END OF
LECTURE