Monday March 30, 2009.

For all of our hard work Mason has granted us a day off from class. Even though it's on account of jury duty we still thank him for a four day weekend. The timing seems really convenient but we won't poke holes at it. Thank you professor Mason!

We should be covering Gauss's law (Chapter 22) on Wednesday for those who want to get ahead.

Answers to my practice test

Answers for practice Celebration

Day 8 March 18

Today we did section 6.1-6.5 on our handout. For the first part of class we started off by solving some problems on the motion of an electron in a uniform electric field. we learned how an electric field affects the motion of an electron with an initial velocity and that E-field causes the deflection of the electron in the oposite direction of E. we did some calculations on our white boards to prove that the deflection is proportional to voltage.. and by using these equations:
F=ma
F=qV/d
and 2D- kinematics equations for the trajectory of the electron we were able to solve for d, and we realized that the deflection is proportional to Voltage(the higher the voltage the greater the deflection). we needed this information in order to understand the second part of class, which delt with function Generators and Oscilloscopes.
For the second part of class we played around with a function Generator, also called (wave generator) which is a device that can produce different voltages in a regular pattern. we connected a speaker to the wave Generator and we played around with different dials and bottons on it and we noticed the sound changes: 1) changing the frequency changes the pitch of the sound. 2) changing(increasing) the amplitude makes the sound louder . 3) changing the function(sine, triangle or square) changes the timbre of the sound coming out of the speaker. After that we learned how to use an Oscilloscope and we connected in to the function Generator and noticed how changing the frequency and amplitude changes the graph(motion of electron)displayed on the screen of the Oscilloscope. we also learned how to calculate the period by just looking at the graph.
for the last part of lab we built capacitive filter cicuits on our breadbord, and we conected it to the Oscilloscope and the function generator. then we collected data for the changes in amplitude and voltage when we change the input frequency. then we graphed the data we got using loger-pro. and we noticed the constant votage drop in the first circuit(capacitor and resister), and the constant voltage in the second circuit(two resisters).
GOOD LUCK ON THE EXAM!
O MY BAD, (CELEBRATION OF KNOWLEDGE!)

Practice test for celebration 1

This is a practice test that I made up. There was no input from Prof Mason on any of these questions, but I thought these were fairly challenging and would pose a good exercise. Prof Mason said he would be handing out his practice celebration on Monday.

Peter's Practice Test

The answers for my practice test will be posted Monday night. I will attempt to have the answers for Masons up on Tuesday night or Wednesday morning. Good luck with studying =)

Edit** For problem one, there is a positive test charge at the point where you need to find the force and electric field.
Problem two, it should be surface charge, not linear

Day 6 March 11, 2009

The first thing we did in the class was a quiz. The quiz is about using the Kirchhoff's Rules to find current in the circuit. Then using the current to find the voltage and the power to compute the total power.

Generally, we use the sum of current and voltage in a loop are both equal to zero to find the current. First, The junction rule I1=I2+I3 will setup the first formula, and the loop rule will create the other two formulas. Then, we can do some algebra for the unknowns in the formulas to find the current. After that, V = IR can be used to find the voltage by current and resistant. Finally, use P = IV to get the power of each resistor, and add them up to get the total power.

I did the questions wrongly, but I found my mistakes soon. All loops have to in the SAME direction. It was a good quiz because I even did not find I was doing something wrong in the homework!


The second part in class was slightly different with the class. We were learning something which is not in the book! The robot project was started! Before touching the hardware, we had to learn some theory for that.

What we learned in this part was the protocol for the devices to communicate. We learn how it works. It translate ASCII code(American Standard Code for Information Interchange), which is commonly used in computer system to represent characters and to some digital signals. The character in ASCII code first translates to 0 and 1, then it reverses the order of the code then translates to positive voltage for 1 and positive voltage for 0.


The third part was doing some labs. We use a voltage divider, a potentiometer to build a bridge circuit to measure the temperature. We take the voltage in the freezing and melting point, which are already known as 100 and 0 degree Celsius, to calculate the room and the body temperature. From the result, we will get a line which show that they are in linear function.

An interesting thing in the lab is that we found this device is really sensitive. It could even catch the temperature change caused by our human body moved away for a few centimeters!

Solving circuits with matrices

Here are the instructions for solving simultaneous equations with your calculator. Note, these directions are for the TI 83 + only. If you have a different model, your procedures will be different.

http://docs.google.com/fileview?id=F.f9c99189-1d8a-4dce-8ad0-9bd68b62ef01

Hmm

Better Be Right Or Your Great Big Venture Goes West

Here's one that's PC, kosher, etc.

SI times are set for the rest of the semester. I have no intention of changing them anymore. Hope to see all there!