May 31, 2007

Things we did in class:



- got our test paper back and corrected it.



- Ms.K handed out a booklet called Kirchoff's Contribution that talks about electric potential, electric potential difference, how to determine the resistance, current, voltage, power for series, parallel, combined networks, Kirchoff's Current Law and kirchoff's Voltage Law.



- a cheat sheet called "Series And Parallel Circuits" that talks about the differences between a series circuit and parallel circuit.



then Ms.K gave us a work sheet to do to test our knowledge and skills..to see if we are really listening and understanding the teachings that she just gave us....~~save by the bell! got only number one on the board...will finish the rest tomorrow...^____^



THE NEXT SCRIBE FOR TOMORROW IS...



JAMIE!!! MWUHAHA!

Test Corrections/Series & Parallel Circuits

New unit

Today in class we went over the questions that we were assigned yesterday in our text books. We got a new sheet on current and another sheet on Cavendish and the first electric meter. Also today in class we got two study guides to do in class. we went over Ch.22 study guide today.
Allen will scribe tomorrow.

Physics Class on May 28, 2007

New Topic: Electric Current

Today's class started off with a video on "Electric Current."

KEY CONCEPTS IN THE VIDEO:

- VOLTAGE = ENERGY (JOULES) / CHARGE (COULOMBS)

- CURRENT proportional to VOLTAGE DIFFERENCE

- CURRENT (AMPHERES) = VOLTAGE DIFFERENCE / RESISTANCE

- I = V / R

- DIRECT CURRENT: A current travelling in ONE direction.

- ALTERNATING CURRENT: A current alternating back and forth.

** Basically the video was an overview on series and parallel circuits.

For the rest of class we were assigned the following:

Read PGS. 469 - 475
Do Practice Problems:
PG. 471 - 472
#1 - #4
PG. 474 - 475
#5 - #8

The next scribe is: GEAR321 (AKA. Eddie)

Sorry i posted this too late, i didn't know i'm supposed to blog last thursday. Well
last thursday Mr. Newman was substituting our class. He assigned our class to answer the " Moving charges worksheet" number 8 to 16 and then we went over the answers. Before the end of the class he gave out 4 handouts for us to do for homework... and that's all i remember.

since someone is chosen to scribe today. i don't have to choose who to scribe next! YEy.

Magnetic force and magnetic field

Ms. Kozoriz is not in class today..so wild cats are everywhere! But Mr. Newman substitute for her on that day!!

Good day everyone..RICARDO is your scribe for today.

First thing he did is... he handed us back the the experiments and assignments.

Then we answer the no. 4 question

(a) Fg and Fe

(b) positive

(c) mg = Eq

q = mg/E

= 1.6 x 10^-18

(d) q = Ne¯

N = q/e¯

= 10e¯

CATHODE RAY TUBE

Electrons leave the cathode and accelerates toward the anodes (p. 536)

The electric field, E, alone produces a force on the electrons Fe = qE causing the electrons to deflect up to x.

The magnetic field, B, alone produces a force on the electrons FB = Bqv causing the electrons to deflect down to y.

(1) To find speed, v, of electrons, adjust B and E until electrons hit point Z

FB = FE

Bqv = qE

v= E/B

(2) To find mass, turn off E. B will deflect electrons to y where

FB = FC

Bqv = mv²/R

m = BqR/v

(3) To find the charge / mass ratio

q/m = v/BR

or

v = E/B

therefore

q/m = E/B²R

In the end of the class..he let us work on questions 8 - 16 in Moving Charges worksheet.

GOOD LUCK to our test on FRIDAY!!!

The next scribe will be...Ms. Makintosh

Review for Friday's Test

Electric and Magnetic Fields

• know the difference between gravitational fields and electric fields
• know the difference between gravitational force and electric force
• what's the diff between a field and a force ?????????
  

HINT: are they vectors? what direction do these vectors take? are masses or charges involved? what are the units for these quantities?

• Coulomb's law - know how to apply it, what constant is used (k=9 x 10⁹),
• what is the relationship between electric force and distance between the charges?
• how is this law similar to Newton's law of gravitation and how is Coulomb's law different from Newton's law of gravitation
• don't forget charges have a unit called the Coulomb;
• charge on a proton is equal to the charge on an electron which is 1.6 x 10^-19

Strength of an Electric Field

• E = F_e /q [field intensity around a test charge; remember a test charge is very tiny and positive]
• E = kq/d² [field intensity due to a single charge]
• E = V/d [field intensity between 2 oppositely charged plates]
• The above 3 formulas all solve for electric field, units being N/C or V/m

Electric Potential/Electric Potential Difference/Electric Potential Energy

• what the heck is potential??? ratio of potential energy per charge
• potential difference is the difference between two potentials-we tend to use potential difference in calculations
• electric potential energy is the amount of energy a charge has due to its position; see the notes on gravitational potential energy and the similarity to understanding e.p. energy
  
• PE = W = qV does this make sense to you? can you explain why potential energy is equal to work????
• know how to solve problems on charged particles that exist between two charged parallel plates (questions 1-4 on Moving Charges worksheet)

Magnetic Fields

• when a charged particle enters a magnetic field its direction changes; an electron will circle one way and a proton will circle in the opposite way
• a magnetic field only changes the direction of a charged particle where an electric field accelerates a charges particle [nice to know this difference]
• the magnetic force acting on a charged particle is given by the formula F_B= Bqv, where B is the magnetic field (measured in teslas), q is the charge (measured in coulombs) and v is the velocity of the charged particle (measured in m/s)
• when a charged particle enters a magnetic field, the magnetic force acting on this charged particle is equal to the centripetal force acting; we can equate these two formulae to solve for unknowns.

F_B= Bqv F_c= mv²/R

F_B = F_c, therefore,

Bqv = mv²/R

Bq = mv/R

m = BqR/v let's you solve for the mass of the charged particle

You can rearrange this formula to solve for the radius of curvature, magnetic field, velocity, etc
See problems 8 - 16 on the Moving Charges worksheet that deal with these formulae given above.

Technologies that use combined electric and magnetic fields are older type of televisions that have a cathode ray tube [not plasmas or LCD TV's], mass spectrometers, loudspeakers-think of objects that have magnets and electric currents.

May 22 2007

we started off with question #7 on the test corrections...
next Mrs.K handed out a booklet which she read over to us...I suggest you read it...its very important.
Then we were assigned questions which she also handed out..."Moving Charges Worksheet"
do questions 1-16 but omit 5 6 and 7

the answers to:
1a) Fg is greater than Fe therefore the drop falls.
b) 3.45 x 10^-4 N [down]

2) 4.6 x 10⁶ m/s

3)2.24 x 10^-13 N (down)

next scribe will be ricardo...

scribe post - lindsay

This is Lindsay scribing for Thursday's class.

We first watched a video on electric fields. Here are the answers from the handout:

1. charge, potential, field
2. determine height above sea levels
3. field lines
4. hard
5. no
6. down
7. elevation; downward slope
8. E=-v/R
9. direction
10. 1/R₂
11. inverse
12. no
13. constant height above sea lel
14. yes; electric fieldis perpindicular to the surface
15. 10 000
16. ionizes the air, electrons accelerate
17. ability to do work when electrons flow; volts
18. Ep=qV
19. charge in chemical form
20. charge, energy electrical field, foce, volt/potential difference

We got another work sheet. Here are the answers:
1. loss PE = gain KE
2. force; distance; W=Fd; increases; equal
3. potential; voltage
4. 1V
5. 12J
6. 5000 V
7. 5000V
8. 5000V
9. .005J
10. charge

We did a lab and hand that in ASAP

We also got more handouts and a worksheet for long weeked homework!

next scribe is...caroline

HEY HEY HEY! Well for those who missed today's class we received a couple worksheets, which pretty much is about ELECTRIC FIELDS. We also talked about the differences between electric force and electric field, also the differences between gravitational field and gravitational force. Also a handout of Electric Potential. That's what we pretty much did in class today. SO FOR THE NEXT SCRIBE........I PICK........



LINDSAY

Heeey guys!!! It is Linger here, and I am your scribe for today and yesterday's class. Anyway, let's begin!!!

Yesterday was the last day of presentations for our projects on Space Exploration. We had Mark present his but due to technical difficulties, others could not present theirs. If you haven't already presented yours, all you need is a group of 5 volunteers to watch your presentation during a lunch hour... it's better late than never! We also had the worksheet called ELECTRICAL FORCES. And that brought us to the end of class. Homework was to finish number five.

In today's class, we corrected the worksheet and Ms. Kozoriz explained how to do number five. We also got a booklet about Coulomb's Law. The first page was based on One Dimension. The second page was about Two Dimensions using equilateral triangles. The third page was about Two Dimensions using squares with indvidual forces and last page was Two Dimensions using squares and adding the forces. The booklet was pretty straightforward. It tells you what to do step by step in certain situations. Remember to convert the measurements to meters if it is given in centimeters. Also, remember to square the value in the denominator!

After discussing this booklet, we were to read pages 415-420 in the red textbooks. For Practice, do problems 1-5 on page 420. Questions 15 and 16 on page 423 are to be handed in for marks and in order to write the unit test.

Well that is it for me. For further help or explanations, make this blog your friend and scroll down to the slides that was posted for today and/or yesterday's class. Anyway, the next scribe is none other than....

BAAAALEEEE!!!!

Coulomb's Law Problems

Hello I'm Albert, the scribe for this weekend.

What we did last friday was....what was it?

oh!some of my classmates including me did the bus ridership.
After we went back, we continue to watch the presentations by our classmates.

The first group was about disasters that happened to astronauts here and in space.
The second group is about the tools that scientists used to explore space.

and that's it..

Next scribe is jillaine!

Project Presentations/Start of Electric Fields

For today's class, students presented their Astronomy projects. And tomorrow, there will be 6 (assuming) other students presenting their projects as well. After the presentations, we started on Electric Fields, and were handed 2 sheets. Tomorrow's scribe will be Albert.

Gravitational and Electric Fields

TODAY was the test of the "Exploration of Space and Low Earth Orbit". It was just a one yellow page and that is worth 42 marks. We used the foolscap paper to answer the test. There are only 13 questions, and worth either 1, 2, 3, 4 or 5 mark each! WEll thats all the information i can give out today just because there are a few students who didnt do the test! Good luck to those who didnt do it yet!


The nex SCRIBE is......VAN

Exploration of Space/Low Earth Orbit Review

Scribe Post

Ok, today we reviewed for the test tomorrow, If you skipped or are in Cal. you should talk to someone that was in class, because the test will become more clearer with the notes. Also we started our presentations on the Space stuff. (I went first, heh bonus marks...................................). And thats it, and remember Ms. K, BONUS MARKS!! :D



Next Scribe is: charlotte

Hello, I'm the blogoer for today, we went over worksheets in class.
We went over the Concept and Devlopment Pratice page 14-1

We had weekend homework on
Chapter 8,
Practice problems
P.166
Q: 5,6,7,8 and

Problems on
P.173
Q: 20,21,22,23

Also went over some formulas in class.... and thats about all we did~! okayyy
~~~~


next is ('0') JILLLLLLLLAINE

Satellite Problems

MAY 1ST & 2ND, 2007

So today in Physics we went over a few worksheets.
See the Slidehare below for the answers.

DO 31-33!!!!

NEXT WEDNESDAY IS THE TEST! (EXCEPT FOR CALCULUS CHILDREN)
PRESENTATIONS ARE ON TUESDAY AND THURSDAY.
***BONUS POINTS FOR PEOPLE WHO PRESENT ON TIME.

May 3 -
We watched a video on satellite motion. Ask Ms. K for the worksheet you missed.

NEXT BLOGGER IS ...JOHNNY!

Escape Velocity Problems

Scribe post: may 1, 07

For Today's class:
- Circular Motion, Work and Energy Test was handed back
- Chapter Eight lab was handed back


After everyone received their work, Ms. K went over the answers for the test.

Here is the demonstration presented to the class:

Energy is used to move the rocket away from the earth. When the rocket moves an infinite distance away from the earth, the gravitational potential energy that the rocket possesses is 0.












Newtons Law of Universal Gravitation:
F_g = (GM₁M₂)/R²

F is proportional to R²

vector quantity

measured in Newtons

Gravitational potential energy:
E_gpe = - (GM₁M₂)/R

E is proportional to 1/R

scalar quantity

measured in joules

After this, we did a transparency sheet, which we handed in. For the rest of the class a Gravitational fields worksheet was handed out. There were also questions on page 273 of the DUCK book... QUaCK QUaccKK!!


NExt scribe is the person who was supposed to be scribe today. =\

What we did this Thursday

I can't really remember what we did on Thursday so this blog will be kind of short.

We had a sub on Thursday, it was Mr.Newman. On this day we went over
the sheets that Ms K had given us the day before. These sheets where about defining
gravitational potential energy. It's basically about how much energy rockets have on
the earth and how much they have after they have left the earth and what is the escape
speed they need to have, i think it's around 11.2 km/s.