Waves Moving From One Depth to Another & Refractions

Hello! This is Mary Ann.

In class today, we got our assignments and test back. We went over the answers for the test, so if you missed any of them..here they are!

1.


This is a transverse wave.


2. amplitude = 1.5 cm
wavelength = 4.5 cm


3. a. longitudinal
b. (i) compression
(ii) rarefaction
(iii) wavelength


4. a. f = 50/10 = 5Hz
b. T = 1/5 = 0.2s


5.
The wave should appear inverted since it hits a fixed end.

6. This is how your diagrams should have turned out.

7.


8.

9. Constructive Interference: occurs when two pulses on the same side pass through each other. This causes the amplitude to increase.
Destructive Interference: occurs when two pulses on opposite sides cancel when overlapped.

10. The main function of a wave is to transfer energy through a medium.

11. a) true
b) meters or cm
c) true
d) normal
e) transverse

12. A standing wave consists of two waves of equal amplitude, frequency and wavelength.

The red dots represent the nodes. The blue dots represent the anti nodes.

After making corrections on the test, we looked into the green booklet on page 9-11 and learned about Waves Moving From One Depth to Another & REFRACTIONS.

When waves move from one depth to another, the frequency does not change. What changes is the speed of the waves. In deep water, the speed of the waves is vdeep = (fdeep)(λdeep). The speed of the waves in shallow water is vshallow = (fshallow)(λshallow). Since the two frequencies are the same it can also be written as vdeep/vshallow = λdeep/λshallow.

In this picture it shows a straw in a glass of water that appears to be broken but it is actually being refracted since half of it is in water and the other in air. Air and water are the two mediums in this case.

*NOTE*
-The 5 questions on Waves in Two Dimensions - Assignment 1 is due tomorrow.
-Our project is due on Tuesday, September 25th.

The next scribe is going to be LAURESSA.

Straight Barrier: Wavefront

Hello everyone, this is Lina with today's scribe post.


We started today's class by going over the worksheet we recieved yesterday about wavefronts and wave rays. It was pretty straight forward.


Here are a couple of definitions for you:

A wavefront is a continuous crest or trough.
A wave ray is to show the direction of travel/transmission of the wavefront.
Remember: The wave ray is always perpendicular to the wavefront. You can also say that the wave ray is at a right angle to the wavefront.

For the wavefront exercise we had to draw the wave rays of circular, straight and irregular wavefronts.

We continued our unit, Waves in Two Dimensions. How exciting. Below is a diagram of how you would determine how the wavefronts are reflected at an angle to a straight barrier.

A few points to remember about this diagram are:

• The Incident wave ray is perpendicular to the Incident wavefront
• The Reflected wave ray is perpendicular to the Reflected wavefront.
• The normal is the straight line perpendicular to the barrier. (not in my diagram, but please bear with me)
• The angle of incidence (theta i) is the angle between the incident wave front and the barrier.
• The angle of reflection (theta r) is the angle between the reflected wavefront and the barrier.
• The angle of incidence is equal to the angle of reflection.
• Another thing you must remember is that the length between the lines of each wavefront should be equal in distance.

The diagram I drew above uses the angle of incidence and reflection as applied to the wavefronts to determine how the wavefronts are reflected.

Another method is to use the angle of incidence and reflection as applied to the normal. Therefore, the angle of incidence (theta i) would be the angle between the incident wave and the normal and the angle of reflection (theta r) would be between the reflection wave and the normal. I don't think we've used this method as of yet, but maybe we might later on.

We also looked at the reflection of waves from a Parabolic Reflector. We worked on drawing our own diagrams during the latter half of the class. We applied our knowledge of the straight barrier to help us out. The only difference is that it's a parabolic barrier.

Tonight's homework is our very first assignment in Waves of Two Dimensions. Complete it for tomorrow's class (or at least try to). ALSO don't forget our WAVES RESEARCH PROJECT due on September 25. Try not to leave it until the last moment like I know we've all done with one project or another. Good luck on that!

If you find anything confusing or anything wrong. Please leave a comment and let me know. This is my first time blogging for school where someone has to learn from it! I hope I didn't make any mistakes.

Last but not least, tomorrow's scribe will be... Mary Ann.

9/18/07

hello my name is Jennifer I am today's scribe.


Today we had a TEST on Waves In One Dimension 0_0
After the test we got a new green booklet called Waves in Two Dimensions & read up to page 6 we also got an exercise on Wavefront's to finish by tomorrow. That is all we did today (:


finally the scribe for tomorrow is . . .
LINA

September 17, 2007

Hello, my name is Kimberley and I am today's scribe.

Today in class we went over the answers to questions 6 - 14 in the green booklet. If you missed any of the answers, they have all been posted on the blog by Mrs. Kozoriz. For the remainder of the class we worked on a worksheet having to do with Superposition, which you can hand in tomorrow if you haven't already handed it in today.

REMINDER: Tomorrow we have a test on Waves in One Dimension. I would suggest looking over everything in the green booklet. Good luck and don't forget to study.

That is pretty much everything we did today. The scribe for tomorrow is Jennifer.

Problems 6 - 14

Hi everyone! I'm Christine and I will be your scribe for today.

In todays class, we worked on CHAPTER 14: STUDY GUIDE worksheet that was handed out by the substitute teacher. And we also corrected them in the end of the class. Here are the answers for the people who didn't get all the answers.

14.1 Wave Properties

Types of Waves

1. mechanical
   
2. material
   
3. electromagnetic
   
4. no


5. particles


6. matter


7. three


8. perpendicular


9. motion


10. parallel


11. motion


12. surface


13. parallel


14. perpendicular


15. single


16. continous


17. vibrating


18. harmonic

The Measures of a Wave: Frequency, Wavelength, and Velocity

1. shortest
   
2. motion


3. vibration


4. second


5. hertz


6. Hz


7. f= 1/T


8. T


9. f


10. wavelength


11. lambda


12. high


13. low


14. v=lambda(frequency)
    

Amplitude of a Wave

1. maximum


2. equillibrium


3. more


4. energy
   

14.2 Wave Interference

Waves at Boundaries Between Media

1. amplitude


2. frequency


3. properties


4. the same as


5. equal to


6. incident


7. transmitted


8. energy


9. reflected


10. most


11. little
    
12. inverted


13. errect?


14. frequency


15. wavelength


16. speed
    

Superposition of Waves

1. independently


2. displacement


3. sum


4. displacement


5. superposition


6. the same


7. greater


8. shape


9. size


10. opposite


11. zero


12. destructive interference
    

Standing Waves

1. undisturb


2. destructive


3. displacement


4. constructive


5. standing


6. stationary
   
7. standing still

And thats all for the worksheet. Make sure that you have the right answers.

For homework,make sure that you finish questions 6-14 from the green booklet. And also, dont forget to study for the test on Tuesday, Septemeber 18th.

And that was today's class. The next scribe will be... KIMBERLEY

September 13 2007

Hi i am Richard and today i am the fifth period physics class scribe

Today we corrected the Chapter 14: Vocabulary review work sheet. If you did not get all the answers or any of the answers here they are;

1.Standing wave
2.Period
3.Destructive interference
4.Node
5.Amplitude
6.Normal
7. Principle of superposition
8.Transverse wave
9.antinode
10.Frequency
11.Interference
12.Wave length
13.Angle of incidence
14.surface wave
15.constructive interference
16.Trough
17.Diffraction
18.Angle of reflection
19.Longitudinal wave
20.Wave Pules
21.Refraction
22.traveling wave
23.Crest
24.Law of reflection


Then we went through the Green booklet. We looked over these sections

D. Reflection
E. Wave Transmission in Two Media
F. wave transmission and Partial Reflection in Two Media
G. Wave interference and the Principle of superposition
I. Standing waves: The formation of a nodes


After that we went over question 1 - 5 in the green booklet if you missed the answers here they are:

1. Longitudinal and Transverse Wave
2. f = 10 crest
. --------- = 0.1 Hz
. 100s


3. f = 580 kHz = 580 x 10 ^3
. v = 3 x 10 ^ 8 m/s
. Wavelength = ?
. v = f (wavelength)
. wavelength = v 3 x 10^8 m/s
. --- = --------------
. f 580 x 10^3 Hz
. Wavelenght = 520m

4. Wavelength = 2.5 cm = 2.5 x 10 ^-2m
. v = 1470 m/s
. t = ?
. v = wavelength/ t
. t = wavelength 2.5 x 10^2 m
. ------------ = --------------- = 1.7 x 10 ^-5 s
. v 1470 m/s

5. v = 450 m/s wavelength = 0.18 m A = 2.0 mm

a)

b) f = v 450 m/s
. --- = ---------
. wavelength 0.18m
. f = 2500 hz

c) T = 1/2500 = t x 10 ^ - 4 s

d) 1 km = 1000m/8 x 10 ^ -3m = 1.25 x 10 6 5 cycles / km

e) t = 1.25 x 10 6 5 cycles x 4 x 10 ^ -4s
. -------------
. cycles
. t = 50 s


After all that we should Finnish questions 6 - 14 in the green booklet


Welll That's what we did in class today and the next scribe will be .. christine d. ...