More on Kinematics...

Hello :)

Thanks to Roger (-_-), I am now your scribe for today.

If you recall last Friday, we worked on some problems/questions from the book. Today, we corrected numbers 1-7 on Page 129. We also corrected Study Guide 4.2: Components of Vectors.
Here are the answers...

PAGE 129 #'s 1-7

1.) 65N - 32N = 33N [E]

2.)
a. vector D and vector C: ----------> 10 units
b. vector A and vector D: -> 1 unit
c. vector C and vector A: ---> 3 units
d. vector A and vector C: ---> 3 units
e. vector E and F: no vector or a "." (dot)

3.)
a. 100N - 75N = 25N [up]
b. 100 + 75N = 175N [down]

4.)
a. 200km/h + 50km/h = 250km/h
b. 200km/h - 50km/h = 150km/h

5.)
a. vector C and D: *I think there was a mistake on this one in the book, but I didn't get to write it down :(*
b. vector C and E:
x=10.63
c. vector D and E:
x=8.7

6.)
a. A+C+D: -------> 7 units
b. D+E+B:

c. B+D+F: zero


STUDY GUIDE 4.2: COMPONENTS OF VECTORS
1.) b
2.) b
3.) c
4.) b
5.) d
6.) a
7.) c
8.) c or b
9.) b or c
10.) c
11.) c
12.) c
13.) c
14.) c

Sorry if some of the answers that I put here are incorrect. Just ask our fellow classmates if you think that the answer is really off.

After the corrections, we were given a handout about Constant Velocity and Constant Acceleration. Ms. Kozoriz explained what "constant" meant.

constant = uniform = same = never changes

Constant Velocity is a velocity that always stays the same.

Constant Acceleration can also mean Changing Velocity.

She also told us the alternate formulas for constant velocity and constant acceleration.

Constant velocity
delta d = velocity * delta t

Constant Acceleration

acceleration = (V₁- V₂)/(delta t)

displacement = ( (V₁+V₂)/2 ) * (delta t)

After that, we had the rest of the class time to work on new worksheets. One was to practice using the formulas with problems. Another was sketching motions in graphs.

I don't really do well on explaining things, so pardon my lack of information (-_-")

That's all for now. I hope that I stated enough everything that happened in class today.

*edit: Almost forgot, the next scribe will be Moot a.k.a. Fajipico. Chyeaha :)

Sayonara~!

- Charchar (:

Chae: October 16, 2008 (:

Hi there! This is Charizze, your scribe for today ^-^

First of all, I would like to remind all of you guys that we have a test tomorrow [Friday, October 17] about the Sound Unit.

Well, I was a tad late for class today but I didn't miss a lot. They already started answering the Problems in the Sound Unit Booklet when I arrived. I only missed questions number 1 & 2, but I got the answers from others. I was surprised because I thought we were to answer the problems for homework. But Ms. Kozoriz just went over it as a review for tomorrow's test.

Anyway, here are the answers:
1.) Larger ear - easier to pick up sound (low frequency)
2.) 10 * 10 * 10 = 1 000 dB
3.) It can hear higher intensity sounds
4a.) Amplitude
4b.) Frequency
5.) Vibrating of the sound waves carry energy
6.) 16 times louder or 10 000 the intensity
7.) A medium -> air, water, wood, etc.
8a.) Intensity - quantitive way to measure sound
Loudness - objective / point of vew
8b.) Frequency - exact value
Pitch - can vary
Skipped #9
10a.) 529Hz - 524Hz = 5 Hz
10b.) t = 1/f => 1/5 = 0.2 s
11a.) 5 s
11b.) f = 1/t => 1/5 = 0.2 Hz
Skipped #12 & 13
14.) 440 + 5 = 445
436 + 9 = 445
Skipped #15
16.) wavelength = v/f => 331m/s / 261.6 Hz = 1.27m
length = wavelength/4 => 1.27m / 4 = 0.316m
17.) The wavelength of sound will increase.
18.) Lower pitch
19.) Higher
20a.) v = 331m/s + (23) (0.6) = 345m/s
20b.) d = vt => (345m/s) (10*10^-3 s) = 3.45m
21a.) None
21b.) Lower frequency
21c.) Higher pitch
22.) 4:5:6 => G B D
G = 384 Hz
B = ? => 5/4 * 384 Hz = 480 Hz
Skipped #23, 24 & 25
26.) c = 256 Hz
c 1 = 256 + 256 = 512 Hz
c 2 = 512 + 512 = 1024 Hz
Skipped #27 & 28

Those that were unanswered (skipped) are not going to be on the test.


We were also given a worksheet to answer based on the scale on the overhead.

Here are the answers for the Decibel Scale Worksheet:
1. 90 dB
2. Soft whisper(70 dB) and Bedroom at night (10 dB)
3. Average Classroom (50 dB) and Inside a compact car (70 dB)
4. Jet airplane (120 dB)
5. Soft whisper (10 dB)
6. Average classroom (50 dB)
7. Heavy truck (90 dB)
8. Jet airplane (120 dB)
9. 2*10^-5 = 20 dB -> Soft whisper
10. 2*10^-1=20N/m^2 => 120 dB

I'm sorry if some of the answers here didn't seem right. I suggest you ask our fellow classmates for more information.

That's what we practically did for the class. We just prepared for tomorrow's test. Just to make sure, study everything that we did for the Sound Unit.

Good luck on the test you guys! :)

Next scribe is.. well there's one more left and it is abbas.