Course: Physics 101, Conceptual Physics Spring 2002
For information on grading, text, course philosophy, instructor, etc, look at the "handout" page. Assignments will be posted on this page.
Click on to jump to specific chapter:Ch 1, Ch 2, Ch 3, Ch 4, Ch 5, Ch 6, Ch 7, Ch 8, Ch 9, Ch 10, Ch 11, Ch 12, Ch 13, Ch 14, Ch 15, Ch 16, Ch 17, Ch 18, Ch 19, Ch 20, Ch 21, Ch 22, Ch 23, Ch 24, Ch 25, Ch 26, Ch 27, Ch 28, Ch 29, Ch 30, Ch 31, Ch 32, Ch 33, Ch34
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(will be almost identical to table of contents of Hewitt at least as of now) and ongoing Lecture Notes (Topics will be almost identical to table of contents of Hewitt at least as of now)
January 29: Chapter 1Introduction (s), About Science
Read Chap 1 and 2 (particularly note review questions Ch 2 #'s 4-7, 19-21, 25. These arenot to be turned in) and fill out . do Practicing Physics pp. 1-pg. 4
For extra credit - Text: Project, p 18.
or- go through the tutorial atwww.physicsplace.com and print and turn in your results.
Or, take the quiz on Ch 2 at the same site and report the results.
quiz next time from Chapters 1 and 2 and the homework.
names of neighbors, check with your neighbor
Physics - the basic science
Tries to explain (develop theories ) for physical phenomena of universe in mathematical terms that can then be tested experimentally, expresses results mathematically.
Math - requirement - algebra
(equations) so I can write equation, use things like area of circle, circumference of circle, etc., Many physical phenomena most clearly understood by mathematical relationship. Use proportions - example of triangles to illustrate, then extension of triangles to size of earth, discuss Eratosthenes 235 BC 800 km Alexandria to Syene. shadow 1/8, so similar triangles, distance 1/8 radius, 8 X 800 = 6400 km radius.
- an idea to be tested. After a group of related hypotheses have been verified, they can form a theory.
- an experimental behavior that always occurs.
January 31: Chapter 2 - Newton's First Law -Inertia
Assignment (for next time):
Read Chapter 3 (note RQ3: 2-4, 7-9, 10-11,16,18-19,24-26), Practicing Physics pgs. 5-6 and Ex2: 20, 22 (note the abbreviated notation I use),
do the C2 quiz at Physicsplace,, turn in printouts of the graded answers
Or do Ex2: 23,26,
Aristotelian physics; Copernicus,
Newtons First Law: inertia "Motion continues" (Objects are lazy)
Gailileo's inclined planes
Net Force, Equilibrium, Support Force, Equilibrium Force, The Moving Earth,
Aristotelian physics; Gailileo, description of motion: speed (speed = distance/time), velocity (depends also on direction), acceleration, free fall. Acceleration caused by gravity at sea level: g » 10 m/s2
summary of relations
For many purposes, we will write the same equation as:
speed = (total distance covered)/(time interval)
acceleration = (change of velocity)/(time interval)
velocity acquired in free fall = acceleration of gravity · time;
distance fallen in free fall, from rest
= 1/2 gravity · time squared;
We will use g = 10 meters/second2 , so d = 5 m t2
examples of free fall, distance, speed, calculation of acceleration
February 5: Chapter 3 - Linear Motion
Assignment (for next time)
Read Ch4, RQ's. Do Practicing Physics pp. 7 -10 (PP:7-10), Ex3:31, Prblm3:4,.
Project, p 52 (turn in a brief half-page write-up, describing what you did and your results.
Or-view the Ch3 videos at Physicsplace, write a brief report <1 page, describing each video
Motion is relative
Speed = Distance/time (think miles/hour, or miles per hour)
Instantaneous vs. average
Or: speed = (total distance covered)/(time interval)
In physics, velocity is defined precisely as giving the speed and the direction. It what we call a vector. Again, have average and instantaneous. But a velocity may be changing even though the speed is held constant. (How?)
Acceleration: rate of change of speed
E.g., miles per hour per second - how many miles per hour the speed changes per second
Velocity change = acceleration X time
v = at
acceleration = (change of velocity)/(time interval)
Distance = avg speed X time
= (1/2 X acceleration X time) X time
or d = 1/2 at2 (= 1/2 a x t x t )
Free Fall, Acceleration caused by gravity at sea level: g » 10 m/s2
Discuss question of forces on objects falling at same speed
February 7: Chapter 4 - Newton’s Second Law
Read Ch 5, RQ's. Do PP pp11-17, Prblm4:2; Project 2, pg 66 (half page writeup).
Do 2 of the remaining projects.
Or Do Prblms4:7,8
Or-view the Ch4 videos at Physicsplace, write a brief report <1 page, describing each.
Second law: force, mass and acceleration (F=ma or a = F/m)
Units: newtons= kgm m/s2
Force: applied force accelerates an object – push or pull.
Acceleration resisted by inertia (mass)
Net force – resultant of all applied forces (add vectors)
Sum of forces = zero: equilibrium (no acceleration, but can be moving –dynamic - or at rest - static)
Depends on weight, not area
Static larger than dynamic
(fluids, including air) – air resistance. Terminal speed
Free Fall and non-freefall – air resistance
Force yields acceleration
Proportional to weight, friction coefficient
Static and kinetic
Mass and Weight
Kilograms and newtons (weight of 1 kilogram = 2.2 pounds)
Mass resists Acceleration
Free Fall – acceleration = g
g= F/m » 10 m/s2
Length and direction
Head to tail, parallelogram methods
February 12: Chapter 5 – Newton’s Third Law
Read Ch 6, do Practicing Physics PP6:21-23), Ex6:1,20,35,36,37; Prblm5:4
Read and report on Ch 5 Videos (one page total report)
Or do Prblm5:2,3,6.
Forces and Interactions
Third law: action and reaction (equal and opposite forces)
Defining the system
Support forces (constraint forces, reaction forces, normal force)
Examples: Block on table, donkey and cart, rocket, road, ball and bat, ball and wall, two skaters pushing off, rifle and bullet, earth and moon
head to tail method, parallelogram method of adding two vectors
Using right triangles
February 14:. Chapter 6 - Momentum
Assignment (next time)
Read Ch7, through pg. 112, do Practicing Physics pp. 25-30 Ex7:12,25,46
Review several of the links at Physicsplace to other sites, for Chapter 6 or 7 e.g., The Physics Classroom; write a brief report ranking those sites (at least 2) on which you found most and least helpful .
Or (And /or) do Prblm6:3,8
Highlights, Ch 6
(= mass times velocity=mv)
= Force times time =change of momentum
=F Dt = m (Dv/Dt) Dt= m Dv = D(m v)
Says, apply a force for a time, causes change in momentum)
Increasing momentum: bat, bow and arrow, golf drive, loose coupling of train cars.
Decreasing momentum gradually: catching hardball, diving into water (not concrete), falling on a mat.
Momentum transferred? – ball against wall: more if bounces or sticks?
"Conservation of momentum"
Isolated system (!) then momentum is constant (Smvinitial = Smvfinal)
Eg. Kinetic balls
February 19: Chapter 7 - Energy
Read Ch8, paying attention to the review questions (!) , esp 4,9,15,26,35
Do Practicing Physics :31à 36, Prblm7: 6,10
Review several of the links at Physicsplace to other sites (e.g., The Physics Classroom), for Chapter 6 or 7; write a brief report ranking those sites (at least 2) on which you found most and least helpful.
Or do Prblms7: 3, 4.
Work, power, energy, kinds of energy, conservation of energy
Work = force ´ distance (cf. Impulse) = newton meters = joules
Power = work/time; the rate of doing work (cf. velocity) = joules/sec = watts!
So 1 kWh (what you are charged for by PGE) = 3.6 million joules. In terms of work, the joule is small. (if you are a cross-word fan, you’ll also see ergs they are even smaller = 1/10 millionth of a joule. A food calorie is 4.2 kJ (k = 1000 = 103) Also Hewitt notes that gasoline has 40 MJ/liter (M = Mega = 106)
Then: energy = ability to do work
Comes in many forms.
LAW OF CONSERVATION OF ENERGY (a big one!!)
Conservation of Energy in popular sense vs. in physics sense?
At what point in its motion is the KE of a pendulum bob the greatest? The least? Half its maximum? What is the PE at each of these points?
Conservation – Kinetic and Potential –
1. speed at bottom of incline vs. dropped from edge?
2. Efficiency – the most work one can get?
3. Work done lifting vs. holding up – work done by a statue? (difference of biological vs. physical work)
Some class questions
Can something have energy without momentum? How about kinetic energy? How about momentum without energy?
Why is there no work done when the force is perpendicular to the velocity of the object?
If a golf ball and Ping-Pong ball move at the same kinetic energy, which has the greater speed? Similarly, in a gaseous mixture of heavy (say O2) and light (say H2) molecules, which "diffuses" faster?
Does a car use more gas when its lights are turned on? Does the overall consumption of gas depend on whether the engine is turned on when you are using the lights?
A pair of identical lumps of clay collide and come to rest as a result. Is momentum conserved? Is kinetic energy conserved? Is total energy conserved?
Consider the swinging balls demo we saw. Why is that that if we release two balls, two balls pop out, and not one ball at 2X the speed?
February 21: Chapter 8 – Rotational Motion
Read Ch 9 (to pg 166) and Ch 10 (to pg 188 only); look at the review questions, esp. RQ9:6,7,9-11,14-18, 20; RQ10:1-17
Do Practicing Physics pp 37-45, , Ex10: 6 (Note: some people are unaware that the answers to the Practicing Physics sheets are given at the end of the booklet. You should try to answer from your reading, but then look at the answers and try further to understand. The purpose of the Practicing Physics pages is to assist your understanding of the reading.)
Review several of the links at Physicsplace to other sites (e.g., The Physics Classroom), for Chapter 7 or 8; write a brief report ranking those sites (at least 2) on which you found most and least helpful.
And/Or do Ex9: 2,16,25 and Prblm8: 5,6.
rotational inertia (~ m r^2),
e.g. balance pole, using arms, etc
(how fast it rotates or goes around) (~v/r )
(=mvr, ~ rotational inertia ´ rotational velocity)
torque that which causes rotation acceleration
(=r F, ~ lever arm ´ force), (units: foot-lbs or newton-meters)
conservation of angular momentum
(no torques) (mvr)Initial= (mvr)Final, BUT since an isolated body can change its rotational inertia (relative to its center of inertia), it can change its rotational velocity – e.g., cats, divers, skaters, etc. (demo on turntable)
center of mass
(essentially same as center of gravity), about which free body rotates, can think of all mass centered there, extended body acts like point mass.
Example, girl on plank – 40 kg, 100 kg, 10 m
Vertical from center of gravity over base, so no torque tending to rotate-
centripetal (NOT centrifugal) force
result from inertia – bodies want to go in straight line, must be forced to turn – think of string and rock.
February 26: Chapter 9 - Gravity AND Chapter 10 Projectile and Satellite Motion; End part 1(Quiz on part 1 next time: bring ZEUS form)
Read Ch 11, do Practicing Physics PP49-52
Again, go to Physicsplace, review a couple of the links concerning Ch 9 or 10, write a page about, what they helped you with.
Or view the videos associated with the chapters, write a sentence or two on each (they are good, but use Quicktime, are jerky on my computer.)
Newton’s Law of
Comments on importance
Impact on culture
Fundamental force, shapes universe
Other fundamental forces, electromagnetic, nuclear strong, nuclear weak.
F=Gm1m2/r2, ~masses of each, ~ 1/r2
G = 6.7 x 10-11 N m2 /kg
Relationship to weight (F=mg), weightlessness.
Inverse Square Law: Discussion of 1/r2 physical quantities: gravitational force, electric force, light intensity, sound intensity, anything propagated from a point source (paint spray spreading).
tides, effect of moon vs. sun, gravitational field.
Full, new ->"spring tides", 90 deg "neap tides"
Gravity inside a planet, or a shell.
Drop of earth ~ 5 m in 8 km
Free fall d = 5 m after 1 sec: if v ~ 8 km/s, orbit! (Newton’s cannon)
If more -> elliptical
Potential and kinetic energy in orbit,
Does rotation of earth affect?
Launch (ve ~0.5 km/s @ equator
Escape velocity , black holes
ve escape velocity = speed at which object leaves orbit, about 11.2 km/s for earth at surface
ve2 ~M/d (d=distance to center)
For sun (radius ~ re x 100, (re = 6.4 million m or 6 thousand km) ; Ms ~Me x 3 x 106), , ve,S =620 km/s
Speed of light : c= 3 x 108 m/s. Nothing travels faster. IF sun shrank so ve > c, NOTHING escapes, including light! black hole. True if sun shrank to 1/106 (one millionth) or about rS~3 km
earth drops 5 m in 8000 m. (or use 1 m in 1600 m, or about 1 m/mile)
Expansion of universe: a question right now, but regardless, gravity the most important force in nature on the large scale.
The essence: horizontal motion is constant, vertical motion changes as a freely falling body. Dhorizontal = vhorizontal t; Dvertical = vvertical t - 1/2 g t2
Inertia, force, speed, velocity, acceleration, mass vs weight, friction, vectors vs scalars, energy, potential and kinetic, power,
inertia - mass; "lazy", accelerating, going around a corner,
force - and reaction; force due to body = weight =mg
speed - mph, dist/time velocity: net distance
acceleration - rate of change of velocity,
force - always mass times acceleration: newtons; friction force, always opposes motion, ~ mg
vectors - direction and magnitude,
energy: mechanical kinetic and potential: many other forms. joules, calories (vs. kilocalories), kWh.
Power: rate of using or changing energy: watts
Tides - non-uniform pull of moon (sun's pull much stronger)
momentum, angular momentum, the conservation laws (3),
units: kg, m, s, N, joules, watts,
weight mg, momentum mv, kinetic energy 1/2 mv2, gravitational potential energy mgh, rotational inertia ~mr2
angular moment ~ rotational inertia X angular rate of rotation ~ mvr
centripetal acceleration: mass on string -> tension (rock seems to pull "outward" but goes in straight line when released - inertia!)
Conservation of momentum - no outside forces in direction of motion
Conservation of angular momentum - no outside twists - earth absorbs, etc. (bicycle,
Conservation of Energy (but must define the system carefully - e.g., refrigerator)
February 28: Chapter 11 - The Atomic Nature of Matter; Chapter 12 Solids (part 1 quiz at end)
Assignment: (for next time
Read Ch 13 and 14. Do Practicing Physics pp. 53-57
Do the scaling tutorial at Physics Place, turn in a report on what you did (and learned)
Do and write a report on projects 13: 2& 3. This could be turned in on the 9th.
The Atomic Nature of Matter
Greeks – speculation of a smallest (Democratis)
18th –19th century chemistry – combination of elements ->individual atoms, weights (Avogadro, Loschmidt)
Modern understanding – atom – 10^-10 m, joined together, makeup molecules. Molecules vary from 2 atoms to millions of atoms (e.g. protein molecules)
Atoms made of nucleus, electrons, all mass in nucleus.
nucleus – 10^-15m, protons and neutrons
surrounded by thin cloud of electrons (size depends on wave properties)
electrons in shells, electrons neg., protons positive, neutron (like protons) neutral.
Atomic number, atomic mass, Avogadro’s number. Shells, charges outside closed shells determine chemical properties.
Nucleus – protons and neutrons, now know p and n made up of smaller particles "quarks" -
Mass of atom ~ 1/6 x 10^23 grams (H)
Periodic Table – shows shells – similar elements having similar outer shell.
Phases – solid liquid gas plasma
– molecule in regular, fixed arrays, bound together. Binding may be "ionic, covalent, metallic, "van der Walls"; size varies from 2 atoms to millions.
Properties of solids: molecules connected by springs, vibrate as heat up, expand.
Tension, compression, strength of arches
Strength ~area - r^2
Weight ~ volume - r^3
Wind resistance ~ area
Note:PART 1 QUIZ AT END OF THIS LECTURE
March 5: Chapter 13 - Liquids; Chapter 14 - Gases and Plasmas: End part 2
Assignment (for next time): (Quiz on Part 2 postponed to be combined with part 3)
Read Ch 15 Do Practicing Physics pp. 59-60 (there will be a "normal" quiz on this chapter)
Start Reading Ch 16 (through about pg 313), do Practicing Physics pp. 61-62
Do 6 exercises at the end of the two chapters, 3 each, your choice. As usual, report on your efforts and what you observed.
Pressure in a liquid (liquid pressure = weight density X depth)
Bouyancy (weight of displaced liquid): Archimedes' Principle
Pascal's Principle: (pressure transmitted throughout)
Surface tension, capillarity
Atmosphere, atmospheric pressure, mass of air (1 m^3 ~ 1 1/4 kilograms at sea level)
Air Pressure ~1/2 @ 5.6 km,
Weight of air ~ 10 N/cm^2 or 10^5 N/m^2 ~ 100kPa , ~ 10.3 m of water
Gas Law: pressure-volume (Boyle's law - const T)
PV = nRT which says PV= cons't for fixed temp, V~T for fixed P (eg., atmospheric)
Gases cool on expansion -
Air Speed increases, pressure decreases.
Plasma - think neon display
March 7: Chapter 15 Temperature, Heat, and Expansion; Start Chapter 16 - Heat Transfer
Assignment (for next time)::
Finish Ch 16, Read Ch 17, Do Practicing Physics pp. 63-65; start Ch 18 (at least through pg 344),
Do 2 of the excellent and easy projects at the end of 17 and report as to what happened and why.
Review Chapters 12-14
In essence, these chapters teach us that all matter is composed of atoms held together by electrical forces. All materials exist as solids, liquids or gases given the right conditions. Solids are held most tightly; as heat is applied, the solid melts and becomes liquid, and as heat is applied further, it becomes gas. All materials can be characterized by their density (greatest for solids, least for gases) Solids can be in compression or tension. Liquids and gases can only undergo compression, and do not support tension. A important concept for both liquids and gases is pressure (force/area) and buoyancy (uplifting force equal to weight of displaced fluid.) Pressure is the same at the same height in either a liquid or a gas. Additional pressure applied is transmitted uniformly through the fluid. In Ch 15 we find both solids and liquids expand some with increase in temperature, but resist compression. However, gases change their volume greatly with changes in temperature or pressure (V ~ T/P, where T measured in kelvins). Bernoulli's principle says that a gas has reduced pressure where it moves faster.
High Points, Chapter 15 and 16:
scales: relative measure of internal kinetic energy, direction of heat flow, measure - degrees. Temperature Calibration - "fixed points", absolute zero.
quantity - usually calories, Btu's, Calories. Internal amount - heat capacity - touching a hot iron, hot wood, hot Al foil, etc. Water - high heat capacity (water: 1 cal/gm-BIG) e.g. Pie Vs filling
of solids (demo), ocean levels - (more on thermal expansion than change in amount of mass)
Water expands when freezes
3 primary means: Conduction, Convection, Radiation
Conduction: direct contact exchange of heat, usual method between solids
Convection: motion of molecules carrying kinetic energy, exchanging energy (bouyancy)
Radiation: heating by photons, that is, by electromagneitc radiation; e.g., the sun.
? Why do you feel cooler when you move away from a fire, but always the same with the sun?
Example of thermos bottle - controls all three.
March 12: Finish Chapter 16- Heat Transfer; Chapter 17 - Change of Phase:
Finish Ch 18 Look at the review questions. Do Practicing Physics pp. 67-68.
Prblm18:3 or do of the projects at end of 17 (that you didn't do before).
Change of phase: Evaporation (condensation); melting (freezing); absorb heat (lose heat)
Associated with change in connection of molecules to neighbors; more kinetic energy makes it more difficult for molecules to "stick".
Evaporation - those molecules leaving take energy, work of "leaving", leaving less - cooling
Occurs all the time. Higher temp - air holds more water vapor, less likely to condense.
Boiling - change of phase interior of liquid. Occurs at a definite temp for given conditions (temperature, atmospheric pressure) = BP
Vapor bubbles ~ 1 atm internal, increase or decrease by pressure change. Covering a pan reduces heat needed - mostly due to reduction in loss of heat.
Cooling, refrigeration uses, air conditioning, "heat pump"
Kinetic energy added enough to disrupt rigid bonds.
Water- 80 cal/gm melting; 540 cal/gm boiling
Evaporation, Condensation, melting, freezing, latent heat
Evaporation (i.e., boiling) is a cooling process!! (takes away heat)
Latent heat - amount of energy to change phase, temperature remains fixed while at phase
March 14: - Chapter 18- Thermodynamics; End part 3, (Quiz on Parts 2 & 3 Next Time, Bring Zeus form)
Assignment (for next time):
Read Chapter 19, Vibration and Waves; Look at the review questions. Do Practicing Physics pp. 69-72, Ex19:17,18
Ex19:1, 4, 11, 12, 26, Prbm19:7 (show work, always)
Sum of all energy changes = 0
Change of energy = heat in – work out
No heat gained or lost - important for engines, atmosphere - work done = loss of internal energy, cooling; work on = increase of internal energy (bicycle pump)
E.g. Cooling at higher elevations, (~ 10 ° C per km), Chinook winds,
Temp inversion, convection of ocean, mantle
Heat engine (heat to work: cyclic) - Heat flow always hot to cold, for engine, always have heat rejected, ideal efficiency e=(Thot-Tcold)/Thot (T in kelvins)- the best one can do.
e.g., electric power plant (steam), run at superheated steam, 700 K = Thot; 300 K == Tcold; e=400/700 ~60% (actually, most are less, have e~35-45%)
e.g. automobile e (using gasoline) ~ 26% to mechanical (electric cars, ~90%(?), but then times the 40% at the power plant - still, far less pollution))
- a measure of "disorder" - 2nd law says universe tending towards greater entropy.
March 19: Chapter 19 - Vibrations and Waves
Assignment (for next time
Read Chapter 20.Sound and Chapter 21, Musical Sounds. Look at the review questions. Do Practicing Physics pp. 73-74, Ex20.5; Ex:21.8
Do the easy projects Prjts20:1,2 and and Prjts21:1,2
Or Ex19:1, 4, 11, 12, 26, Prbm19:7 (show work, always),
Simple harmonic motion (SHM)
"sine waves" wavelength, frequency, period
frequency = number of cycles (or "shakes" or vibrations) per second
period = T = time for one shake or cycle = inverse of frequency (= 1/f)
restoring force, causes "oscillations" e.g., pendulum, s pring and weight.
frequency - (cycles/sec); period, amplitude
unit: call cycles per second = hertz; e.g., ac current = 60 cycles per second = 60 hertz. KQED at 88.5 MHz (megahertz) = 88.5 million cycles per second)
Like SHM in motion
speed (or velocity) of wave = distance / time; v = l /T = f, the basic equation for waves v = l f, use l (greek "lambda")
wavelength - distance wave goes in one period
Change of speed as cross boundary, e.g. from air into glass
Waves recombine with self - e.g. max and minima from two speakers, or combining with reflection
Constructive or destructive
Standing waves - interference - nodes (where cancel) and antinodes
Waves "bend" some around corners.
Bow wave, shock waves
Sound, v ~ 340 m/s ~
Light (more later) v = 3.00 X 108 m/s
All waves refract, diffract, interfere
March 21: Chapter 20 - Sound & Chapter 21 - Musical Sounds: end part 4
Read Chapter 22 and the review questions. Do Practicing Physics pp75-76
Ex22.1, 3, 7, 10, 17, 20, 29,41
Compression waves, 330 m/s
Sympathetic vibrations, beats
Frequency, "quality", harmonics
energy per unit area, bels, decibels, logarithmic scale (powers of 10) Painful - 1 W/m2 = 120 dB; just audible 10-12 W/m2 = 0 dB, conversation ~ 60 dB, loud traffic ~70-80dB.
Loudness subjective, not the same as intensity
March 25- 29: Spring Break
April 2: Finish Sound, if needed; Chapter 22 - Electrostatics
Finish Sound, if needed; Chapter 22 - Electrostatics
Assignment(As usual, for next time)
Read Chapter 23, Electric Current. Do Practicing Physics pp77-79 (this is complicated and important: we'll finish these next time)
Go to the "secret bells" link from Ch 21 in Physicsplace and do the activity (and briefly report). It's neat!
Review the "Multimedia Physics Studio" animations concerning electrostatics - the links with Ch 22, and report briefly.
Electrical Forces, Electrical Charge
Atoms, electrons, coulombs, conservation of charge
Coulomb's Law - ~q1q2/r2
Cf. Newtons Law of Gravitation
Cf. Heat transfer
Charging, transfer of charge
Charging by induction
Differences between conductors, insulators
The Electric Field (and differences with gravitational field)
"alteration of space"
From (+) to (–)
Conductors shield, insulators change
The Electric Potential
Potential energy per unit charge - "voltage
joule/coulomb = volts
field - measured by volts/meter
Capacitor - stores (+), (-) charge at potential difference
volts X coulombs = joules
battery - converts chemical energy into separated charge at potential difference; again, coulombs X volts = joules
April 4: Chapter 23 - Electric Current
Assignment(As usual, for next time)
Do Practicing Physics pp80-84; Read Chap 24
Coulombs/sec = amperes
"conventional" -> + to –
Electrical pressure – electric potential – volts
Voltage sources – batteries, generators, power supplies,
Speed of electron flow, of electrons
Current ~ Voltage/Resistance: I = V/R (amps = volts/ ohms)
Comments in electric shock – heart electrical pattern, destruction of nervous system
Body resistance ~ 102 – 106 W
Potential difference: biological, shock, language
120 V avg.
Voltage times current; watts = amps X volts
Series, parallel circuits
House circuits often 15 amps (1500 watts/110 volts = 14 amps)
April 9: Chapter 24 -- Electric Current(concldd) Magnetism
Assignment(As usual, for next time)
Read Chap 25 Do Practicing Physics pp 85-88
Prjct24:1 (Interesting and easy; as always, brief writeup)
and/or Ex24:3,4,9,1019,20 and Ex 25:26,27 OR Prblm25:2.
N, S poles
All magnets have both
N = "north-seeking" points to North, etc.
Opposites attract, like repel
Source – electrons in "orbits", electric currents
Forces on moving charges
Probably due to currents in core.
Shields us from high energy particles emitted by sun
(picture of recent solar flare see sohowww.nascom.nasa.gov/hotshots/X17)
Selection of great (!) aurora pictures as a result of above, see
April 11: Chapter 25 - Electromagnetic Induction, (Quiz on Parts 4 & 5 Next Time, Bring Zeus form)
Assignment(As usual, for next time)
Read Chap 26 Do Practicing Physics pp 89-90 and Ex26:1,2,9,10,20,27.
Projects 1-3(simple, fun)
Field lines (or flux) cutting wire - induces current
Demo: "induction coil"
Rotate coil in field = generator (produces voltage)
Max voltage - right angles between field lines and movement of wire.
Transformers (coupled flux)
Couple changes of flux (recall flux = field through an area)
if ac in one, changing flux in other, produces voltage.
Voltage/# of turns)A = Voltage/# of turns)B
NA / NB = VA / VB
But power (VI) remains constant.(energy conservation)
Power transmission - Hi V , lo I
VI - constant, so use high V, low I, so have less heating loss in wires (I2R). Usually 10.4 kV to transformer by house, hundreds of thousands of V for cross country transmission, 220 V into house
April 16: Chapter 26 - Properties of Light (Quiz on Parts 4 & 5 This Time, Bring Zeus form)
Read Chapter 27, do Practicing Physics pp. 91-92, Ex27: 2,3,13,14 (see 15),20
A great (and fun) web site for this chapter (see extra credit above, also)
Do the Tutorial on Color at Physicsplace, turn in the result of the quiz (this is a very good one)
Or go to
Changing magnetic field produces changing electric, vice versa -
Velocity = c = 3 X 108 m/s = velocity of light
In 1 cycle at 1 GHz (1x 109 ); period = 10-9 s, d = 3 x 108 m/s x 10-9 s = 0.3 m, size of a computer; or, distance light travels in a nanosecond = 30 cm.; in a microsecond = 300 m, etc.
EM spectrum -
radio (meter to 100's of meters), microwaves (fractions of m down to millimeters), infrared (millimeters to microns (10-6 m)), visible light (10-6 to 10-7 m), ultraviolet (10-7 to 10-9 m), x-rays (10-9 m to 10-11 m ), "gamma rays" (10-11 m to ??)
Transparent vs. opaque materials:
ties to vibrations of electrons in atoms.
Shadows, sharp and diffuse,
Shadow from sun: Umbra, penumbra
Metallic reflection - vibrations of electrons.
Optical illusions: go to (!!!)
April 18: Chapter 27 - Color
Assignment: (next time, of course)
Read Ch 28, Reflection and Refraction. Do Practicing Physics pp. 99-104
Do at least 3 of the 6 projects at the end of Ch 28. Easy, informative. Provide a one page (at most) report of what you did and saw.
(if you did Practicing Physics 93 - 99, that'll count as an extra credit assignment.
Selective reflection and transmission
A great (and fun) web site for this chapter (see extra credit, also)
Mixing colored light and colored pigments
Additive and Subtractive, Complementary colors
Some color phenomena
April 23: Chapter 28 - Reflection and Refraction
Assignment: (for next time
Read Chapter 29, Light Waves. Do Practicing Physics pp 105-108
Do any two of the projects at the end of Chapter 29
OR Answer any eight of the Exercises for Chapter 29, including at least 4 even numbered.
Highlights (the link to the simulations I'm showing today is
equal angles, virtual image, plane, concave and convex mirrors, reflection from diffuse and polished surfaces.
Light bending as moves obliquely from different speed media.
Basis for lenses.
Different speeds for different wavelengths in some media. Cause of separation of colors by a prism and by rainbows
Total internal reflection
Since light from lower speed media bends away from perpendicular, at some angle there's no room (fig 27.36).
Prisms in binoculars
Optical fiber "light pipes."
: April 25: Chapter 29 - Light Waves
Read Chapter 30, 31. Write answers to Exercises 13,18,19, 21,22 28,29 44,45
Huygen's principle -
that any element of a wave front can be viewed as generating new spherical waves that add to give new wave fronts. Allows explanation of diffraction, interference.
Waves bend around a barrier (Fig 28.7), spread when going through a slit. The longer the wavelength the greater angle of bending (explains why one hears sound waves behind a wall between you and speaker, e.g.)
Constructive and destructive addition of waves, produces "interference fringes."
When white light passes through a thin film (such as reflecting from water with an oil film on top - the thin film, see colors as a result of some waves adding, others canceling.
Direction of light vibrations, absorption of one.
April 30: Chapter 30 - Light Emission, (bring a trash CD to use as a diffraction grating) Start Chapter 31 - Light Quanta
Finish Ch 31, , Answer Exercises Ch31:3, 6, 11, 16, 35; Read Ch32. Do Practicing Physics pg110
Atoms: excitation, emission of radiation.
Emission spectra, absorption spectra, Fluorescence, incandescence, phosphorescence, lasers
Ch 31: Highlights, Ch 31
Birth of the Quantum theory
Quantization and Planck's Constant
Photoelectric Effect, the photon
Wave Particle duality
Double Slit Experiment
Waves as Particles Wave-
The double slit experiment
May 2 :Finish Chapter 31 - Light Quanta; Chapter 32, The Atom and the Quantum
Finish Ch 32 Do Exercises Ch32: 3, 5, 11, 12, 13, 15, 18, 23. Practicing Physics pg 111-112; First Reading Ch 33, do Practicing Physics p 111-112,
Ch 32 Atomic Spectra, Bohr model, relative sizes, Explanation of quantized levels, Quantum mechanics, particles as waves, Complementarity
Electron Waves and Quantum Mechanics
Explanation of quantized levels, particles as waves standing waves in atom.
Probability description of electron, etc.
May 7 Finish Chapter 32, : Chap 33 - The atomic nucleus, radioactivity (continued)
Assignment (for next time)
Read Ch 34, do Practicing Physics pg 113, Ex 34:11, Problem 34:2
Problem 34:1.Ex 34:18
x-rays, alpha, beta, gamma rays
Effects of Radioactivity
Dosage and exposure
Discovery of the Atomic Nucleus
The Nucleus (Isotopes, nuclear stability, half-lifes, natural transmutation, artificial transmutation, carbon dating)
Atomic number, atomic mass number
Half-lifes, carbon dating
p's and n's, short range force and coulomb repulsion
combinations, stability and decay Transmutation
natural transmutation, artificial transmutation,.
kinds of changes of nucleus, driving force and mass-energy equivalence E=mc2
Basics of a fission reactor
May 9: ADVISING DAY - NO CLASS (BUT YES LAB!!)
May 14 Chapter 34, Nuclear Fusion and Fission
Begin review (see next assignment). There will be a Quiz next time covering parts 6 and 7
Copy, fill in, and turn in copies (keep a copy for study )the sample quizzes for parts 1-7
These will not be graded, but doing them will add to your extra credit score
p's and n's, short range force and coulomb repulsion
combinations, stability and decay
driving force and mass-energy equivalence E=mc2
The basic curve of nuclear stability
Nature seeks lowest energy state!
Nuclear Reactions, cont.' - Fission and Fusion
Nuclear forces - contact attraction, charge repulsion
92235U and 94239Pu; U(238) à U(239) à Np(239) à Pu(239) (breeding)
Basics of a fission reactor
The triplets, Hadrons and Leptons
May 16 :: Modern Physics wrap-up, Quiz parts 6&7 )(bring ZEUS form Assignment: Review, final preparation
Review your work and quizzes for questions for next time class review
(May 17: Last day of instruction for semester)
May 23: Final Exam: Thursday May 23rd, 1045 – 1315, Room Sci 201:
Don't forget to bring a full page Zeus form and a pencil.