6/9/2015Lecture I1 Physics 122, Fall 2012 Course overview

04/18/23 Lecture I 1

Physics 122, Fall 2012

Course overview


Introduction

• Instructor Prof. Regina Demina

• Office B&L 367

• Phone 275-7357

• Email [email protected]

• Office hour Mon 3-4 pm


Novosibirsk


Objective of the course

• thorough understanding of the basic physics concepts

• ability to use them in applications


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


Workshops and Homework• Solving problems systematically is important.• Peer-lead study groups – workshops• Participation in workshops will count 5% of your final grade. • 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: "Dev Ashish Khaitan" <[email protected]>


Midterm exams• There will be two midterm exams during the

semester.• Both will count. • There will be no makeup exam. • You can bring a calculator, a pencil and a ruler.• 40% of your grade.


Final Exam

• December 17, 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


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.

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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.

mailto:[email protected]

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Grading

• Workshops: 5%• Homework: 5%• Hour Exams: 40%• Final Exam: 40%• Laboratory: 10%• Total: 100%• 90% or above: A 88-89.9 – A- 85-87.9 – B+• 80% - 85% : B 78-79.9 – B- 75-77.9 – C+ • 70% - 75%: C 68-69.9 – C- 65-67.9 – D+• 60% - 65%: D

• Under 60% : E

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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

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PHY 121• Kinematics – how do objects move?

– Trajectory, displacement, velocity, acceleration, time

• Dynamics – why do objects move?– Mass, force 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

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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

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Inside nucleus

• Protons and neutrons consist of quarks, called up and down quarks

• Quarks are believed to be elementary

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Nature’s scales

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My research - LHC

Alps• Large Hadron Collider located in Europe (France and

Switzerland)

• Circumference 27 km;

• 7TeV(2010-2011)8TeV (now)14 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

H

04/18/23 Lecture XII 22

H4l

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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.

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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).

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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.

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Induced chargeBodies 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.

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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 have lost electrons.– B have gained electrons.– C have lost protons.– D have gained protons.

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Coulomb’s law • F – force between two charges(N)• Q – electric charge (C= Coulomb)• r – distance between the two

charges (m)• k – constant

229

221

/100.9 CNmk

r

QQkF

+ +1 2

12F 21F

1 2

-+12F 21F

space free ofty permittivi

/1085.8

4

1

0

22120

221

0

NmC

r

QQF

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System of chargesCalculate the net

electrostatic force on particle 3.

Input:– Q1= - 86C= - 86.10-6 C

– Q2= + 50C= + 50.10-6 C

– Q3= + 65C= + 65.10-6 C

– r13=60cm=0.60m

– r23=30cm=0.30m

229

221

/100.9 CNmk

r

QQkF

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This week

• Sign up for workshops if you have not done so.

• Workshops start next week.

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My research – getting inside atoms

• Fermilab • 40 miles west of

Chicago • Tevatron – at the

moment world’s 2nd highest energy collider – 2 teraelectronvolts– 6.28 km

circumference

• Top quark discovery - 1996

Documents

6/9/2015Lecture I1 Physics 122, Fall 2012 Course overview