Physics 101 Spring 2012

05/11/12:
We spent the first half of class talking about the bending of light in a gravitational field (one of the major effects of general relativity). I talked a bit about gravitational lenses and the global positioning system, which are both pieces of evidence in support of general relativity, and finished up with a quote from Richard Feynman's book "The Pleasure of Finding Things Out". During the second half of class we did a short participation activity and reviewed the main ideas from throughout the semester.

05/09/12:
Today I started class by reviewing the idea of reference frames, and then explained the two postulates of special relativity. Next, we talked about the effects that result from those two postulates. We saw how two events which happen at the same time for one observer don't necessarily happen at the same time for another observer. We also talked about time dilation (the idea that moving clocks run slow), and I did an example using the time dilation formula. I also went over length contraction (moving rulers are shortened), and how that effect only happens along the direction of travel. Finally, we talked about the correspondence principle, which states that new models of how things work must be consistent with past observations that supported old models. This applies to special relativity, which yields the expected results when applied to situations of very slow speed compared to the speed of light.

05/07/12:
We spent the first part of class today going over nuclear fusion, and how the process works in the Sun specifically. We learned that both fission of large nuclei (those larger than iron) and fusion of small nuclei (those smaller than iron) release binding energy according to Einstein's mass-energy equivalence formula E = mc². We watched this demo of the proton-proton chain to see the three steps in the fusion process. I did an example problem on the board demonstrating how to use Einstein's equation that showed that the amount of energy released in each fusion reaction is actually quite small. Next we turned our attention to the fields of special and general relativity. I talked about "regular" Newtonian relativity, and introduced the idea of inertial reference frames and non-inertial reference frames. On Wednesday we'll talk more about the postulates of special relativity.

Reading for Monday: Chapters 35 and 36

05/04/12:
Today we did course evaluations at the beginning of class, and then launched into material on nuclear physics. I talked about the discovery of radioactivity, and the different types of nuclear radiation (x-rays, alpha and beta particles, and gamma rays). We learned about how the strong nuclear force holds the protons and neutrons in a nucleus together, despite the electrical repulsion of the protons. I talked about how we can measure the rate at which an unstable nucleus decays, and how we express the time it takes for half of a substance to decay as the half-life. I also explained how scientists use the half-life of an isotope of carbon to determine how long ago an organism (anything that either is a plant or eats plants) died. Next, we talked about the difference between nuclear fusion and nuclear fission, and typical sources of everyday exposure to (mostly harmless) radiation. I talked a bit about nuclear weapons and nuclear power plants, and we did a short participation question at the end of class. Next time we'll finish up by talking about fusion, and then start relativity.

Reading for Friday: Finish Chapter 33, Chapter 34

05/02/12:
Today we continued to look at quantum physics. We started class with an example showing how to use Plank's equation to calculate the amount of energy carried by a single photon of light, and how to calculate the frequency of light given its wavelength. Next we learned that matter, as well as light, has both particle- and wave-like properties. I talked about how this idea was first proposed by a scientist named de Broglie, and we did an example where we calculated the de Broglie wavelength for a ping-pong ball. I talked about how physicists have confirmed de Broglie's equation by observing diffraction patterns from electrons, and how we can use the wave properties of matter to make electron microscopes. I showed some images created with electron microscopes, and then talked about Heisenberg's uncertainty principle. I wrapped up the chapter by describing some of the debates surrounding quantum physics and its meaning, and the idea of complementarity.

Reading for Wednesday: Chapter 32, first half of Chapter 33

04/30/12:
Today we finished up Chapter 31 at the beginning of class by reviewing emission of light from atoms using this demo of Hydrogen atomic energy levels, and talking about fluorescence and phosphorescence. I also explained what's unique about laser light before we turned our attention to quantum physics. I described the state of physics as a discipline around the turn of the 20th century, and how Max Plank and Albert Einstein used descriptions of light as particles to explain blackbody radation and the photoelectric effect. I explained the specifics of the photoelectric effect, why it did not agree with the classical wave model of light, and how Einstein used photons or light quanta to explain the strange effects measured by Heinrich Hertz and Robert Millikan. On Wednesday we'll continue with more modern physics.

Reading for Monday: Chapter 31

04/27/12:
Today we took the third midterm in class. Scores will be posted on iLearn as soon as I'm finished grading the exams, which should be late next week.

04/25/12:
Today I began class by going over how diffraction works, and why the diffraction gratings we used produced the images we saw. Next, I went over thin films (such as those in soap bubbles or oil slicks) and showed how constructive or destructive interference can cause different colors to appear on the surface of these films. Next, we moved on to Chapter 30, which looks at sources of light. We went over how electrons in atoms can absorb or emit light, and how hot gases and hot solids produce emission and absorption spectra. We used the diffraction gratings to look at the emission spectrum of the overhead lights in the classroom, and I also talked a bit about absorption spectra.

Reading for Wednesday: Chapter 30

04/23/12:
At the beginning of class today I did a quick recap of refraction, and we did an example question of how refraction works and how it changes what we see. Next, we looked at the differences between converging and diverging lenses, and what types of images they produce. We also discussed Huygens' Principle as another way to describe waves of light, and talked about how light interferes with itself (a property that extents to all waves). I drew a diagram explaining constructive interference and destructive interference, and then explained how light is diffracted around boundaries. We did a short demo at the end of class using diffraction gratings to see light spread out into its different colors (or wavelengths).

Reading for Monday: Chapter 29

04/20/12:
At the beginning of class today I spent a few minutes talking about the final exam and how it will be structured. I'll go over the details again as we get closer to the end of the semester. The focus for today's lecture was on two main topics: reflection (light bouncing off mirrors) and refraction (the bending of light due to it slowing down through different materials). First we looked at how light travels based on the "Principle of Least Time". I used the same analogy from the textbook about a lifeguard deciding which path to take through sand and water to rescue a swimmer, based on how fast she can run on sand and swim through water. We then learned the law of reflection, and talked a bit about how we see things in mirrors. Next, we turned our attention to refraction, and learned that refraction happens because light travels at different speeds through different materials. I talked about how scientists use the index of refraction to judge how much a material will slow down light. I also did a demonstration of how light is bent "towards the normal" (i.e., towards a line running perpendicular to the interface) when travelling from a lower n to a higher n. We did a quick voting question at the end of class, and will pick up with lenses next week.

Reading for Friday: Chapter 28

04/18/12:
I started class today with a short explanation of what makes different materials transparent or opaque to different kinds of light. Next, we learned a little bit about how our eyes see, and I did two demonstrations of how our eyes work by turning the lights on and off in the classroom. We talked about how our eyes have two types of light-sensitive cells called rods and cones, and that cones are responsible for the perception of color. Next we talked about the perception of color and color mixing, and how absorption and reflection produce the colors of objects around us. At the end of class we did a short participation activity using the concept of color mixing.

Reading for Wednesday: Chapter 27

04/16/12:
Today we shifted into a new unit of the textbook on Light. We spent most of class today discussing the properties of light. We reviewed general properties for a wave, and learned that light is the result of changing electromagnetic fields. I talked about the different wavelengths and frequencies that light can have, and about the properties of gamma rays, x-rays, UV, IR, and radio waves. We did an example using the speed of light to calculate the wavelength of a radio wave, and I talked about the key differences between how we experience light waves and how we experience sound waves. Towards the end of class I started to introduce the ideas of reflection and scattering, and talked about how light is slowed down when it passes through different materials. On Wednesday we'll continue with more about what makes a substance transparent or opaque.

Reading for Monday: Chapter 26

04/13/12:
Our focus in today's class was electromagnetic induction. We learned that just as a magnetic field exerts a force on moving electric charges, so too does a changing current produce a magnetic field. EM induction states that changing magnetic fields can induce a current through a wire: either by moving a magnet near a wire, or moving a wire through a mangetic field. I demonstrated this by moving a strong bar magnet in and out of a loop of metal. We were able to see the interaction of the original magnetic field and the new induced magnetic field of the loop making the loop swing back and forth. We learned that Faraday's law states that the induced voltage in the wire is proportional to the number of loops in the coil of wire and the area of those loops. I did a demo by increasing the voltage in a coil with 4,000 loops by moving the bar magnet in and out of those loops. I also covered Lenz's law, which tells us that the new induced magnetic field will oppose the original magnetic field (because of conservation of energy). I talked briefly about how electric guitar pickups work using induction, and then we talked about how voltage can be "stepped up" or "stepped down" unsing transformers. I did an example using the equation for transformers, and then talked about power transmission and self-induction. At the end of class, I showed this video demonstration of self-induction (or "back-emf") and explained the physics behind the demo.

Reading for Friday: Chapter 25

04/11/12:
Today we continued with more material on magnetism. I started class with a quick review of what we covered in class on Monday, and explained the answers to our participation question about current-carrying wires. We spent most of class today looking at the force experienced by a charged particle as it moves through a magnetic field (also called the Lorentz force). We did several examples on the board and in groups. At the end of class, I switched gears to briefly talk about the magnetic fields of the Earth and Sun, and other applications of magnetism.

Reading for Wednesday: Finish Chapter 24

04/09/12:
We started Chapter 24 today, which looks at magnets, magnetic fields, and magnetic forces. First I spent a little bit of time talking about the history of the study of magnetism, and how scientists first began to see the connection between magnets and moving electric charges in the 1820's. We learned that all magnetic fields are produced by currents (or moving electric charge), and learned about how moving electrons inside atoms are responsible for the magnetic fields of permanent magnets. I talked about how the magnetic domains are either ordered or randomized in different materials, and did a short demonstration with a magnet and some paper clips. We learned how to draw diagrams of magnetic fields, and then used the right-hand-rule to figure out the magnetic field of a wire with some current running through it. At the end of class we did a short participation activity involving the force between two current-carrying wires.

Reading for Monday: First half of Chapter 24

04/06/12:
I began class today by reviewing the three main quantities we care about when dealing with circuits: resistance (R, measured in ohms), current (I, measured in amps), and voltage or potential (V, measured in volts). Next we learned Ohm's law describing how these quantities are related, and did an example using Ohm's law to determine the current in a circuit. We learned about how to figure out the power used in an electric circuit, and used a car battery charger to demonstrate the difference between circuit elements hooked up in parallel and in series. We finished up class by doing some voting questions.

Reading for Friday: Finish Chapter 23

04/04/12:
Today we finished up Chapter 22 by talking about the electric field as an energy field. We learned that potential energy can be stored in electric fields, and that physicists differences in electric potential energy per unit charge as "voltages". I described how capacitors can be used to create a mostly uniform electric field and thus store energy. We then started Chapter 23 by discussing electric current, and relating it to water current. We'll continue to use this water flow analogy when discussing circuits. We learned that current is measured in units of amperes (or just "amps" for short), and that resistance is measured in ohms. I also explained that current will only exist in a conductor if there is some potential difference or voltage to drive the current. At the end of class I talked about how the amount of current in a conductor is directly proportional to the voltage, and inversely proportional to its resistance.

Reading for Wednesday: pgs. 404-411 (1st half of Chapter 23)

04/02/12:
Today we took the second midterm during class. I will announce in class when the exams are graded, and will post scores on iLearn.

No reading for Monday; review for Midterm #2!

03/28/12:
I began class today with a quick recap of charge, Coulomb's law, and charging by contact or induction. We did several voting questions to make sure everyone understood Monday's class, then talked about electric polarization and how it's related to charging by induction. Next, we learned about electric fields and how to represent them by drawing arrows to indicate direction and strength. I did an example calculating the charge required to produce a given force between two charges, and we started talking about electric potential at the end of class. After the midterm exam on Monday, we'll continue with more on electric potential on Wednesday.

Reading for Wednesday: pg. 392-399 (E-fields and Electric Potential)

03/26/12:
Today we started a new unit on electricity and magnetism. We spent the first half of class talking about the electric force, and how it is both similar to and different from the gravitational force. We also learned that although the electric force is much stronger than the gravitational force, large objects tend to be charge-neutral, so that the electric force doesn't play as big of a role as gravity on large distance scales. We learned more about how charge travels between objects, and I demonstrated charging by induction and charging by contact/friction. We ended class with a short participation activity about what we found most and least confusing in today's lecture.

Reading for 3/26: Chapter 22

03/16/12:
Today we finished our unit on waves and sound by looking at the Doppler Effect and some basic characteristics of sound waves. We looked at standing waves, and learned the difference between blueshifted waves and redshifted waves. I talked about the range of human hearing and other properties of sound waves, including their speed in air. I talked about the decibel scale and the difference between intensity and (perceived) loudness of sound, then talked about the properties of musical sound waves. We learned a little bit about harmonics, and I did a little demonstration by playing some notes and chords on the ukulele.

Reading for Friday: Chapter 21

03/14/12:
Today we spent the first half of class finishing up the laws of thermodynamics. We talked about the concept of entropy, and saw that entropy is increasing in natural processes. I asked everyone to come up with examples of processes which increase entropy for participation before we moved on to waves. Our next small unit covers waves and sound, and we began with describing the basic properties of waves: wavelength, frequency, period, and amplitude. I also described the difference between transverse and longitudinal waves, and demonstrated them using a rope and a slinky. We did a few voting questions to make sure everyone understands these properties, and talked briefly about wave interference at the end of class. On Friday we will finish up with waves by discussing standing waves, the Doppler effect, and the differences between musical and noisy sound waves.

Reading for Wednesday: Chapters 19 and 20

03/12/12:
Our guest lecturer today covered material about phase changes and thermodynamics. First we went over the names for changing from one phase of matter to another, and introduced another phase of matter called a "plasma". Next, we talked about the 0th, 1st, and 2nd laws of thermodynamics. We talked about some examples of each, and did a few voting questions during class.

Reading for Monday: Chapters 17 and 18

03/09/12:
Today we covered material from Chapter 16, which deals with methods of heat transfer. First we looked at conduction, which is the transfer of heat through molecular interactions. We reasoned that fast-moving molecules (in a hot substance) can tranfer their kinetic energy to slow-moving molecules (in a slow substance) through collisions. I gave a few examples of heat flowing due to conduction. Next we looked at convection, which is how heat is transferred through the motions of a fluid. Finally we looked at radiation, or how energy is transmitted through light (both visible and invisible). I talked briefly about the different kinds of radiation that exist, and talked a little bit about waves of light. We ended class with a very important application of heat transfer: the greenhouse effect, and the consequences of the human contribution of more greenhouse gases to Earth's atmosphere.

Reading for Friday: Chapter 16

03/07/12:
Today we covered material from Chapter 15, which deals with heat and temperatures. We learned that temperature is a measurement of the average kinetic energy of the molecules within a substance, and talked about the Celsius, Fahrenheit, and Kelvin temperature scales. Next we learned that if two objects are in thermal contact (usually touching each other), then heat will flow in the form of energy from the higher-temperature object to the lower-temperature object. Once the objects have the same temperature, they are in thermal equilibrium and no more heat will flow. We looked at some different units for heat, and I did some demonstrations of how heat can cause substances to expand. We did a short prediction of how heat expansion would work for class participation, and ended with a few voting questions.

Reading for Wednesday: Chapter 15

03/05/12:
Today we finished up our section on matter by looking at a few principles governing liquids and gases. First, we learned about Pascal's principle, which says that pressure exerted on an enclosed liquid is transmitted undiminished throughout the liquid. This is the basis for most hydraulic lift systems. Next we talked a bit about gas pressure and the atmosphere, and saw that Archimede's principle applies to objects that are completely surrounded by air just as it applies to objects that are completely surrounded by water. We did a voting question to help drive home the point that an object's volume determines how much air (or water) it will displace, and therefore determines how much buoyant force it will feel. I mentioned that the same rules we learned for flotation in a liquid apply for flotation in a gas, and we did several examples of how differences in pressure can help us explain how drinking through a straw works. Finally, we ended class with a discussion of Bernoulli's Principle (that faster-moving gases produce less pressure), and how that allows airplane wings to fly when pitched at a particular angle. I showed this animation of streamlines near an airplane wing, which explains how lift works.

Reading for Monday: Review sections on Boyle's Law and Bernoulli's Principle

03/02/12:
Today in class we started off with a review of the definition of pressure, then did a few voting questions about the relationships between pressure, force, and area. Next, I did an example on the board of how to calculate the pressure exerted by the bottom of a person's shoe due to half of the weight of the person. Next I reviewed the ideas of liquid pressure and buoyant force from Wednesday's class, and we learned about the conditions under which an object will float or sink in a fluid. We analyzed some socratic dialogue between three imaginary students arguing about how lifejackets work, and then I did a demonstration of how we determine the effective density of an object. We used the results of the demonstration to understand why huge iron ships can float, and finished up class with a voting question about icebergs and water levels.

Reading for Friday: Chapter 14

02/29/12:
Happy leap day! Today we covered material from chapters 12 and 13, including topics on solids and liquids. First, we talked about the concept of density, and how it's related to volume and mass. We defined formulae for mass density and weight density, and did an example calculating the density of gold. We also did some conceptual questions comparing the density of ice and liquid water. Next we talked about pressure and defined a formula relating pressure to force and area, and talked about how pressure changes with contact area. I talked about how liquids exert pressure on objects submerged in them, and introduced the concept of buoyancy. I demonstrated the idea of the buoyant force by weighing a cylinder of iron in air and again in water. We learned that the buoyant force is equal to the weight of water displaced. Next time we'll do more examples of pressure and buoyancy and talk about flotation.

Reading for Wednesday: Pgs. 212-216 and Chapter 13

02/27/12:
Today we began a new unit on properties of matter, having finished with mechanics before the midterm exam. We started with Chapter 11, which deals with atoms and atomic structure. We learned about the size and features of an atom, and how to determine the atomic number and atomic mass number of an atom. We also talked about how the number of protons in an atom's nucleus determines which element you have, and looked at the periodic table of the elements. Next we talked about the electrical forces keeping electrons close to the nucleus of an atom, and learned about how the sizes of atoms vary from one to the next. We learned about how to distinguish between different istopes of a given atom, and talked about mixtures, compounds, and molecules. We did some examples comparing the mass of different molecules, and briefly talked about antimatter and dark matter at the end of class.

Reading for Monday: Chapter 11

02/24/12:
Today we took the first midterm in class. I will post exam scores here according to the last four digits of student ID number. Exams will be available for pick-up during office hours, and I am happy to go over the exam. It will probably take at least one week to grade the exam, so I will make an announcement in class when the scores are ready.

02/22/12:
Today we covered material from Chapter 10 on projectiles and orbits. We first examined how the motion of a projectile can be broken up into two portions: constant-velocity motion in the horizontal direction and free fall in the vertical direction. Next, we looked at how fast we would need to throw a projectile so that by the time it falls, we have to take notice of the Earth's curvature. We calculated how fast we would need to throw or launch something to get it into a circular orbit around the Earth. We can also think of this motion in terms of rotation, where gravity is the centripetal force keeping objects in their circular path. We talked about the idea of escape velocity and revisted the idea of black holes from Monday's class. At the end of class we applied the ideas of momentum, force, acceleration, velocity, kinetic energy, and potential energy to look at a planet's orbit.

Reading for Wednesday: Review sections on fast-moving projectiles and escape speed

02/20/12:
Today we covered material from Chapter 9 on Newton's law of gravity. We started with a general description of gravity, and learned how the strength of the gravitational force depends on the amount of mass in each object and the distance separating the centers of the two objects. We also saw how Newton's third law (the one about action-reaction force pairs) is mathematically built into the law of gravity. We did some voting questions imagining a satellite in between Earth and the Moon, and reviewed the idea of how to combine forces to get the net force on an object. I also talked about some applications of gravity, and how we can use the concept to explain why we experience tides and the nature of black holes.

Reading for Monday: Chapter 10

02/17/12:
Today we finished up rotational motion by talking more about torque and introducing angular momentum. I went over the rotational equivalent of Newton's first and second laws using torques, rotational inertia, and angular acceleration. Next we looked at centripetal force, and did a quick example. We had a power outage on campus around 10:40AM, but luckily I had some demonstrations of the conservation of angular momentum that most of the class could still see, even with only the emergency lights on. We'll do a quick recap of angular momentum at the beginning of class on Monday and then move on to gravity and projectile motion.

Reading for Friday: Chapter 9

02/15/12:
Today we started Chapter 8, which looks at the mechanics of objects which are rotating. We defined quantities for angular position, angular speed, and angular acceleration, along with rotational inertia and torque. I did several demonstrations: one where plastic hollow tubes with weights in different locations were spun. The tube with the weights spread out at either end was much harder to spin than the tube with weights near the rotation point. We also did a demo watching two metersticks fall by rotating, and the one with a large lump of clay on one end fell more slowly due to its higher rotational inertia. Finally, we did a race watching a disk and a ring of the same mass roll down an inclined plane, and saw that the disk (which has more mass near the rotation point) won the race. Finally, we talked about torque in detail and how it depends on both the stregth of the force applied and how far away from the rotation point the force is applied (the lever arm). We'll continue with more rotation next time, starting with center of mass.

Reading for Wednesday: Chapter 9

02/13/12:
I started class today with a quick recap of potential and kinetic energy, and did some examples of how each are calculated. Next, we talked about the Work-Kinetic Energy theorem and used it in an example to determine how far to push a block to accelerate it from rest to 10 m/s. I drew some parallels between the relationship between impulse and momentum and the relationship between work and energy, then talked about conservation of energy. We did several examples and voting questions up until the end of class.

Reading for Monday: Finish Chapter 8

02/10/12:
Today we started by talking about the differences between elastic and inelastic collisions, and did a longer example problem using conservation of momentum. Next we moved on to Chapter 7, which looks at work and energy. We definted the quantities of work and power, looked at their units, and did some examples calculating work in a few different situations. I explained how work depends on how much force is exterted on an object over a distance, and that what really counts is the portion of the force that acts parallel to the direction of the motion of the object. At the end of class I started talking about potential (or stored) energy and kinetic energy, which is where we'll pick up on Monday.

Reading for Friday: First half of Chapter 8 (pgs. 122-130, up through section on Torque)

02/08/12:
Today we started off class by defining momentum and impulse, which are other tools we can use to analyze mechanics problems beyond just using Newton's Laws of motion. We learned how to calculate an object's momentum, and what factors influence the impulse delivered to an object. Next, we talked about conservation of momentum: the idea that momentum as a quantity, cannot be changed unless there is an impulse, and that momentum can be transferred from one object in a system to another. I talked about differen types of collisions, and did some demonstrations of how momentum gets transferred between objects during a collision.

Reading for Wednesday: Chapter 7, focus on Work-Kinetic Energy Theorem and conservation of energy

02/06/12:
I started class today with a few more examples using Newton's third law. We discussed the classic "Stubborn Donkey" problem, and got some more practice using Newton's laws to explain physical situations. I quickly reviewed all three of Newton's laws of motion, then went on to explain how to add vectors that are not pointing in parallel directions. We did some demonstrations of how vectors add and how they can be broken down into vertical and horizontal components by having two of your classmates hold up a heavy bookbag with a long piece of rope. Next time in class we will begin talking about momentum and energy.

Reading for Monday: Chapter 6

02/03/12:
Today we did a Socratic Dialog participation activity in small groups for the first ten minutes of class, so that everyone could get a chance to talk about the concepts behind Newton's 2nd law. Next, I lectured a bit about other kinds of forces: weight, friction, and air resistance. I did a demonstration of the difference air resistance can make using a glass vacuum tube with a poker chip and bits of paper inside of it. Next, we moved on to Newton's 3rd law, and I did some examples of how to identify paired forces in a few different situations. We also did an example using gravity to understand the differences between how to apply Newton's 2nd law and 3rd law.

Reading for Friday: Chapter 5

02/01/12:
We started class today by talking more about free fall, and we did two examples illustrating how velocity and distance change during free fall. Next, we started looking at the Newton's 2nd law (Chapter 4) and the relationships between force, mass, and acceleration. I explained the difference between mass and weight, and talked about how acceleration is proportional to force, but inversely proportional to mass. We did an example of how to determine the mass of an object when given the force acting on it and its acceleration. Next time we'll do some more examples with Newton's 2nd law.

Reading for Wednesday: Chapter 4, focus on Fig.s 4.2 and 4.11

01/30/12
I started Chapter 3 (Linear Motion) today. We covered the definition of speed and velocity, and investigated the differences between the two. I also talked about acceleration, and did some examples calculating acceleration and velocity. Next, I did a demonstration of how velocity and acceleration are both vectors, and how they don't have to point in the same direction by running back and forth in front of the classroom a few times at varying speeds. At the end of class we started talking about free fall, and how velocity and distance change during free fall. We'll continue with more on free fall in class on Wednesday.

Reading for Monday: Chapter 3, focus on differences between speed, velocity, and acceleration

01/27/12:
Today we covered Chapter 2, which deals with Newton's 1st Law and inertia. I covered the basic idea of force, and how you need to have a force in order to change an object's motion. I did a demonstration of inertia with a block on a stick and a hammer, and went on to explain how force is a vector quantity. We learned how to combine forces that are acting in different directions, and did some practice problems combining forces. I talked about the four fundamental forces and which ones we'll be dealing with this semester. Towards the end of class we went into detail about the normal (or support) force, and what it does.

Reading for Friday: Chapter 2, focus on Fig.s 2.5 and 2.6

01/25/12:
The class roster has now been uploaded to WebAssign, so make sure you register as soon as possible. We started class today with a quick description of physics as a science, then talked about the different kinds of SI units we'll be using in this course. We did a quick review of scientific notation, and did an example of units conversions (converting the time of one year into seconds), and talked about significant figures (or sig figs). After a couple of voting questions, we got a head start on Chapter 2, which deals with inertia, and did a short participation activity at the end of class. On Friday we will finish up Chapter 2.

Reading for Wednesday: Chapter 1 and Appedix A of Hewitt

01/23/12:
Welcome to Physics 101! Today we spent most of class going over the syllabus and the structure of the course. I collected a questionnaire from everyone to keep track of first day attendance, and we got some practice using the voting cards we'll use throughout the semester. On Wednesday we will start by talking about the nature of science, and then go over material from Chapter 1 and Appendix A of Hewitt.