Sep 3, 2013 ... Forth Edition by Douglas C. Giancoli. • Class web site /www.pas.rochester.edu/~
regina/PHY122. • Lecture notes;. • Homework assignments.
Course overview Physics 122, Fall 2013
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Introduction • • • • •
Instructor
Prof. Regina Demina
Office
B&L 367
Phone
275-7357
Email
[email protected]
Office hour Mon 3-4 pm
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Novosibirsk
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Objective of the course • thorough understanding of the basic physics concepts • ability to use them in applications
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Sources • Text book Physics for Scientists and Engineers, Volume II Forth Edition
by Douglas C. Giancoli • Class web site /www.pas.rochester.edu/~regina/PHY122 • Lecture notes; • Homework assignments • Workshop modules • Equation sheets for tests, test solutions • Important dates and links 9/3/13
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Workshops and Homework
• • • •
Solving problems systematically is important.
Peer-lead study groups – workshops Workshops start next week Participation in workshops = 5% of your final grade, need to participate (not just attend!) in at least 10 workshops to get full grade.
• Homework problems are similar but not identical to workshop modules
• Homework problems = 5% of your final grade.
• Questions on workshop scheduling: "Ryan Waldman"
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Midterm exams • There will be three midterm exams during the semester.
• Two best will count.
• There will be no makeup exam.
• You can bring a calculator, a pencil and a ruler.
• 40% of your grade.
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Final Exam • December 18, 7:15 pm • Final exam is based on the entire course PHY122.
• Last homework will be based on the entire course to give you more time to prepare for the final.
• 40% of the final grade
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Equation sheets • No notes or equation sheets may be brought to exams.
• However, a sheet of useful equations will be provided during the test. You can view these sheets in advance, will be linked from course schedule on the web.
• Please note that past experience has shown that having equations available does not guarantee success -- understanding is the key. 9/3/13
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Labs • The laboratory is a required and integrated part of the course.
• A passing grade in laboratory is required to pass the course: 10% of the grade
• Questions should go to
[email protected] • NB. I am not allowed to reveal this person’s identity.
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Grading • • • • • • • • • •
Workshops: Homework: Hour Exams: Final Exam: Laboratory: Total:
90% or above: 80% - 85% : 70% - 75%: 60% - 65%:
• Under 60% : 9/3/13
A
B
C
D
88-89.9 – A
78-79.9 – B
68-69.9 – C
E
5%
5%
40%
40%
10%
100%
85-87.9 – B+
75-77.9 – C+
65-67.9 – D+
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PHY122 too easy? You still have a chance to switch to PHY142
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How to study for physics class • Look through lecture notes first – In lectures I’ll give you all the information that you need to survive in this class
• Read the suggested sections from the text book – Read the summary first – concentrate on what’s important – Don’t overdo the reading part, try to understand not memorize – Pay attention to • Figures, spend more time on them than on text • Examples, try to work out the problem yourself first • Equations (try to analyze, e.g. if the charge doubles the Coulomb force on it will double as well)
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How to do physics problems • Use the “How to do physics problems” guide posted on the course web site • While doing first several homework assignments and workshop modules stick to it religiously • This practice will help you during the tests • PHY122 is a lot more abstract than PHY121 – well developed procedures will help you to get started 9/3/13
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PHY 121 • Kinematics – how do objects move? – Trajectory, displacement, velocity, acceleration, time
• Dynamics – why do objects move? – Mass, forceè work – Conserved quantities • Energy – potential and kinetic • Momentum
• First step into micro world – kinetic theory – Mechanical laws work on molecules – Heat is a form of energy 9/3/13
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PHY 122 • What is the origin of forces? – So far we considered only one true force – gravity – Next step – electricity and magnetism • Static – new conserving quantity – electric charge • Dynamic – DC and AC • Magnetic field • Electromagnetic waves – light
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Phases of matter • Solid,
liquid,
gas
Matter is built of atoms
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Inside atoms • Atoms have structure = nucleus + electrons • Nucleus has positive electric charge • Electron has negative electric charge • Nucleus has structure = protons and neutrons • Electron so far is believed to be elementary = unbreakable 9/3/13
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My research - LHC Alps
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• Large Hadron Collider located in Europe (France and Switzerland) • Circumference 27 km; • 7TeV(2010-2011)à8TeV (now)à14 Tev(2014) • LHC has uncovered the mechanism behind mass - 2012 • Discovery of particle known as Higgs boson • Prof Hagen (Rochester) – one of the six people who predicted this mechanism
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Hàγγ
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HàΖΖ*à4l
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Electricity • There are two kinds of electric charges – positive and negative. • Like charges (++, or --) repel, • unlike charges (+-) attract.
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Inside atoms • Atoms have structure = nucleus + electrons • Nucleus has positive electric charge • Electron has negative electric charge (Q= -e) • Nucleus = protons (Q=+e) and neutrons (Q=0) Electrons are much lighter and thus more mobile than protons or neutrons. 9/3/13
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Electric charge • The net charge is conserved. • Electric charge is measured in Coulombs. • Electron has negative charge (e=-1.60.10-19 C), nucleus – positive. • Atom is electrically neutral. • Nucleus is heavy, electron is light. Usually charge is transported by electrons. • By acquiring more electrons bodies become negatively charged (Q= -Ne .e) • By loosing electrons bodies become positively charged (Q= +Ne .e). 9/3/13
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Insulators and conductors • In solids atoms and their nuclei are “locked” in their position and hard to move. • Insulators have complete or almost complete electron shells – these electrons are tough to move around. • Conductors (usually metals) have one or two electrons on the outer shell – “free” electrons. 9/3/13
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Induced charge Bodies can be charged by • Conduction (direct contact) • Induction – create charge separation – Break into pieces – “Ground“ one end – charge leaks into the Earth.
Always think, where electrons went – they are the ones to move. 9/3/13
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Electroscope Electroscope – a simple device to detect electric charge.
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Test problem #1 • Two electrically neutral materials are rubbed together. One acquires a net positive charge. The other must – A – B – C – D
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have lost electrons. have gained electrons. have lost protons. have gained protons.
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Coulomb’s law • F – force between two charges(N) Q1Q2 F =k 2 • Q – electric charge (C= Coulomb) r 9 2 2 • r – distance between the two k = 9.0 ⋅10 Nm / C
F12
+
1
+
F12
1
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+
F21
2
F21 2
charges (m) • k – constant
1 Q1Q2 F= 4πε 0 r 2
ε 0 = 8.85 ⋅10 −12 C 2 / Nm 2 ε 0 − permittivity of free space Lecture I
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This week • Sign up for workshops if you have not done so. • Workshops start next week.
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