Wednesday November 26 2008

Today in class the first thing we did was correct the questions that was assigned yesterday. On page 172 in the green book, Questions 9 to 12

Question 9 Answer : F = 8.0 x 10 ^-10 N
Question 10 Answer : F = 6.49 x 10 ^-8 N
Question 11a Answer : Fg = 491.3 N
Question 11b Answer : w = 490 n
Question 12 Answer : m = 9.01 x 10 ^-31 kg

The Next thing that we did was Watch some of the old Space Exploration Projects.

After that we then were taught to derive some formulas.




For number 1 you cancel out one of teh masses on each side.
For number 2 you cancel out one of the masses and radius on each side.
For number 3 you just cancel out one of the masses on each side.
She also gave us a forth one but she handed out a handout for this one.

The Next thing that we did was a review sheet for chapter 8.
And that was todays class the next scribe will be Kamil

November 25, 2008

To start things off we had gone over the questions on the Activity Sheet on Artificial Satellites and the Concept-Development practice page 14-1.

Here are the answers to the following:

Activity Sheet on Artificial Satellites

1) When the projectile is launched to a speed of 8km/sec
2) If it travels less than 8km/sec
3) around 8km/sec - 11.2km/sec
4)Yes, due to the atmosphere drag
5) about 850km - 35 800km
6) Yes
7) Yes, collisions with air particles slowly act to circularize the orbit and slows down the satellite. This causes it to drop to lower altitudes.

Concept-Development 14-1

1. d) Circle
e) Ellipse

2.d) Yes, the forces are the same strengh and are at equal distance
e)Yes, there is no acceleration
f) 90 degrees
g) No, "F" and "V" are perpendicular
h) No work is done
i) remains constant
j) remains constant

Right after we corrected the questions from the green book on page 172, and learned that the first 5 questions involves using this equation
(T1/T2)² = (R1/R2)³

Answers
1) 12 years
2) was to be handed in to Ms. K (answer: 19.2 Re)
3) 3.0724 Re
4) 22.63 years
5) 0.35Tm
6) 6.11 x 10^-9N
7) 4.17 x 10²³N
8) 5.84 x 10^-10N

Finally on the same page we are to work on next 5 (I think) questions.

Homework:
Questions 9 - 13 on page 172, Green book
Space projects are going to be due very soon!

Next scribe will be Richard

Physics November. 24, 2008

Today in class we watched a video about the "same same" teacher and the topic about the video was about the relationship of energy, gravity, and speed required to orbit and escape the earth, and the 's gravitational field, the vectors associated with the path of flight/orbit, and the shape of the orbits known as ellipses. It also explained why the paths of orbits were ellipses and how Kepler didn't see this visualization. Lastly, it went over the potential and kinetic energy relationships of the orbits.

Handouts on the "escape speed", "falling moon", "artificial satellites", and a practice sheet were given out.

Shelly blogs next..

I See Heavenly Bodies ;-)

Hello Hello,

This is Benofschool and for the record I didn't beg for this position as today's scribe. Well today we had a substitute and that person shall stay nameless because I do not have her permission to display his/her name online. Anyways we were assigned gravitational orbit and gravitational force questions from the Physics Green Textbooks. The questions are found on page 172 and questions #1-8 and including 8. For reference you can look at the past worksheet with planetary constants like the radii, period, and mass or you can look at page 159. I'd prefer the worksheet because it has all of the numbers required to answer the questions.

Sorry for the short scribe, but this is counted as a scribe. =P

Next scribe is Dana, but if he doesn't do it the next scribe will be Richard...

Okay I'm off to have a studying filled weekend =D

November 20, 2008

Walking into class, having a great day so far. Lawrence gave me a wonderful present. To scribe for today, what a nice guy huh? (Sarcasm). Anyways, let's get going.

The first thing we did today was the GRAVITATIONAL FIELDS WORKSHEET handed to us by the substitute teacher we had on November 19, 2008. (Mrs. Karras)

Next we were handed back our Transparency Worksheet (10)
I got the answers right so here they are.

1. 2M, 2M has the greatest force.
2. 2F.
3. Equal.
4. M1, M2, 2D = 1/4 F.
5. F=1.40 x 10 ^- 8 N.
6. 1/9 F.
7. 3F.
8. 3/4.
9. Remains the same.

Near towards the end of the class, we were handed a "Gravitational Potential Energy" booklet. If you don't have this booklet, get it because some very useful formulas are found at the back of this booklet.

Using this booklet, we were given a assignment (not due or anything) to finish in class. It's called "Gravitational Potential Energy Questions." Sorry I can't really give out the answers due to me leaving my Physics stuff in my locker or I might have lost it, I wouldn't know. Let's end this post by saying the next scribe is Benchman who begged me in class to blog for the weekend.

Wednesday, November 19, 2008

So by the blog, apparently Dana was supposed to be scribe, but upon my arrival to class, (Which was delayed due to my Phys Ed. Class, which took place at Sargent Pool) apparently Tony was chosen to be scribe, and since it was his birthday (which for some reason acts as a power of Veto), it was passed on to me. Honestly now.


Anyways, We basically went over the worksheets Ms. K assigned us the day prior. Mrs. Karras was also substituting.

Answers:

Study Guide 8

21) Cavendish used a rod with a ball on it, suspended from a thin wire. It also included a Large ball, a support, a mirror and a light source.









22) Force of attraction between the large and small balls caused the rod to rotate. It stopped rotating only when the force required to twist the wire equaled the gravitational forces between the balls.

23) F = G(M1*M2)/d^2 --> G = F*d^2/M1*m2 --> (6.67 *10^-11N)(1m)^2/(1kg)(1kg) = 6.67*10^-11 N*M^2/kg^2

Moving on, we went over the Chapter 11: Gravitational Interactions worksheet.

So since we know that if either mass in the equation for the law of universal gravitation is doubled, the force is doubled. Also we know that if the distance doubles, the force is one fourth of the original force.

1) If both masses are doubled, the force quadruples.

2) If the masses are not changed, but the distance of separation is reduced to 1/2 to the original distance, the force gets quadrupled.

3) If the masses are not changed, but the distance of separation is reduced to 1/4 the original distance, the force is sixteen times as much.

4) If both masses are doubled, and the distance of separation is doubled, the force remains the same.

5) If one of the masses is doubled, the other remains unchanged, and the distance of separation is tripled, the force is 2/9 of the original force.

6) The force remains the same (Force would be multiplied by 9, but because the distance is multiplied by 3, the force would be reduced to 1/9th of the original, keeping the force the same)

We then went over the Universal Law of Gravitation worksheet.

1) 7.41 * 10 ^-14 N

2) 81.82kg (In my case)
b)801.8 N (In my case)
c)180 lbs (In my case)

3)
a) Doubled
b) One quarter times
c) Four Times
d) Sixteen times

4) 1.62 * 10 ^ 6m

We were then handed a transparency sheet, which was later handed the same day. We were also given a Gravitational Fields worksheet, that would be due tomorrow I assume.

Next scribe is Tony.

Tuesday, November 18th, 2008

Today in class, we got some examples of what our big project should look like and then we went over a couple of sheets.

Here are the answers for the worksheets we corrected:

Chapter 8 Study Guide (Universal Gravitation):

Inversely
Square
F=G(M1 x M2)/R²
Force
R
Constant
Doubled
Halved
1/4

Chapter 8 Study Guide (Newton's Use of His Law of Universal Gravitation):

Second
Kepler's

Chapter 8 Study Guide (Weighing Earth):

Henry Cavendish
Attraction
Law of U.G.
6.67 x 10^-11 N x M²/Kg²

Chapter 8 Study Guide Section 8.1: Motions in the Heavens and on Earth:

1. True
2. True
3. False
4. True
5. False (Sun)
6. False (Area)
7. False (Ratios)
8. False (1st and 2nd)
9. Equal
10. 1
11. Rio -> need to calculate you need
Tio -> T + R of another of Jupiter's moons
12. C
13. A
14. D
15. B

We were assigned questions 16 - 23 on the "Chapter 8 Study Guide Section 8.1: Motions in the Heavens and on Earth" sheet and we also got 2 worksheets to do: "Universal Law of Gravitation" and "Chapter 11: Gravitational Interaction".

That's all folks, next scribe is Dana.

Kepler's Three Laws Videotape

No one was selected for scribe in physics, so I'm assuming today's scribe post is up for grabs.

I am zeph. zeph is scribe. Today's scribe post has been zephed!

Answers to "8.1 Motion in the Heavens and on Earth: Kepler's Laws of Planetary Motion" and "Kepler's Three Laws Videotape" are given below.

---
8.1 MOTION IN THE HEAVENS AND ON EARTH

Kepler's Laws of Planetary Motion

Tycho Brahe studied the motion of the planets in order to be able to PREDICT astronomical events. He believed that EARTH was the centre of the universe. Johannes Kepler believed that THE SUN was the centre of the universe. He analyzed Brahe's data, and developed THREE laws of planetary motion. One law says that the paths of the planets are ELLIPSES with THE SUN located at one focus. Another law states that an imaginary line extending from the sun to a planet will sweep out equal AREAS in equal amounts of time. According to this law, planets move FASTEST when closest to the sun and move SLOWEST when farthest from the sun. Kepler's last law states that the ratio of the squares of the PERIODS of any two planets in orbit around the sun is equal to the ratio of the CUBES of their distances from THE SUN. This law can be states as an equation, (T_A/T_B)^2 = (R_A/R_B)^2. To use this law to calculate the period of a satellite, you must know the RADIUS of its orbit and the PERIOD and RADIUS of the orbit of another satellite.

---
KEPLER'S THREE LAWS VIDEOTAPE

Answer the following questions based on the videotape entitled "Kepler's Three Laws".

1. What planetary model did Johannes Kepler believe in?
Copernican

2. What planet's orbit did Kepler analyze?
Mars

3. How far off from a circle was the oribt of Mars?
8 min arc or 1/4th of the apparent width of the moon

4. What type of curve can explain the orbit of Mars?
ellipse

5. In an ellipse, is the total distance from 1 pin to the string and then to the other pin a constant?
yes

6. The name given to a single point in an ellipse is the __________.
focus point

7. Focus is the Latin word for __________.
fireplace

8. How would you describe Kepler's childhood?
poverty and illness

9. What journey did Kepler undertake in 1600 and for what purpose?
went to see Tycho Brahe in Denmark to learn more astronomy

10. What was a main interest of Tycho Brahe?
astronomy

11. How did Kepler obtain the careful observations that Brahe made during his lifetime?
stole it

12. Was the Copernican model of the universe easy to justify scientifically?
no

13. What were some of the problems that faced Kepler in discovering the secrets of the sky?
planets are in motion in its orbit and rotates on axis

14. How many pages of calculations did Kepler have?
about 900 pages

15. What does "in opposition" mean according to the positions of Mars, Earth, and sun?
Mars is in the same position as the Earth and the sun

16. Can any circle viewed obliquely be termed an ellispe?
yes

17. In ancient history, which group of people studied conic sections?
Greeks

18. Is a parabola a popular shape in our world today?
yes

19. In your own words, describe he term eccentricity?
how flat an ellipse is

20. State Kepler's 3 laws.
a) 1st: Each planet moves in an ellipse with the sun as its focus.
b) 2nd: A line from the sun to each planet sweeps out equal areas in equal times.
c) 3rd: T^2 directly proportional to R^3

---
HOUSEKEEPING
Homework:
* 8.1 Motion in the Heavens and on Earth Study Guide
* Exploration of Space Project due Thursday, November 27.
Next scribe is ERICT.

friday

Hey classmates.
in today's class we did a lab on chapter 8.
HAVE A GREAT WEEKEND.

Wednesday 12, 2008

On Wednesday we actually didn't do much.Mrs.K gave a review on circular motion and work and energy. Which took half of the class, afterwords Mrs.k gave us a brief article about space.Also we were given this assignment where you have to write about a historical technology or a particular planet, indicating whether its inhabitable or not, and such. The assignment is due on Nov 27, and a presentation is required.

Nov. 10

Today in physics we had a Remembrance day assembly, yeah.
Well, we also had physics class.
Today in physics we had a substitute teacher, named Mrs. Karras, she's pretty cool.
Anyways, we didn't do much at all in physics class, we just corrected the questions we got over the weekend. They were p.213-214 questions: 1-5, 9-12, 17-20 and p.237-238 questions: 1-4,12-14, 20-21.
The next scribe will be Yonas, cause he said we were absent.. and we fell for it. Life sucks.

Energy Transfer & Hooke's law

For today's class, we were given some time to work on the worksheet called "Energy Transfer" and and we also went over them. And for anyone who didnt get the answers here they are.

1. Potential Energy and Kenetic Energy are the two types of energy that occurs in the spring- block system.


2. PE is the energy position and KE is the energy due to motion.


3. The kinetic energy is at a maximum when the distance = 0 , because thats when speed is the greatest.


4. The potential energy is at a maximum when the speed = 0.


5. As the potential energy increases the kinetic energy decreases. And this is an example of a closed system.


6. The sum of the KE and PE stays constant. This demonstrate the Law of Conservation of Energy.


7. The PE and KE equal to 4 times during one cycle.


8. No, this cycle will not repeat forever because the displacement decreases.


9. If the cycle stops the energy goes to the board.


10. If the spring were vertical gravity would've affected the box which would result in an open system.

After going over the answers, we were given the rest of the time to work on our Lab from the class before. And we were also given question to do from the green book pages 213-214 questions number 1-5, 9-12, 17-20 ; pages 237-238 questions number 1-4, 12-14, and 20-21. the questions are DUE ON MONDAY.

AND DONT FORGET THAT THERE WILL BE A TEST ON THURSDAY, SO DONT FORGET TO STUDY !

And the next scribe is FRANCIS.

Ugly Weather, Winter's Coming... Let's Scribe!

Hello :)

So today's class was very straight forward, we were given a lab to do related to Hooke's Law. We had to find the relationship between the extension in an elastic spring and the applied force. The materials that were needed for the apparatus were a stand, ring clamp, elastic metal spring, and a meter stick. We had to attach the spring to the ring clamp and adjust the spring so the lower end is on the zero point of the meter stick, or at a constant spot during the observations. Then we had to make a chart similar to the one on the paper like so:



Then we had to hang mass on the spring, and record the extension of the spring. We had to repeat the previous step for each of the mass given. Then we had to plot the graph (question 6 on the paper) and answer questions 7-11.

Don't forget to answer the Practice questions 1-5 shown on the back of the lab paper. The answers are given just show your work and how you got those answers.

Make sure to hand in yesterday Wind-up Toy Lab that was due today.
Today's lab 10.1: Hooke's Law is due TOMORROW!

No school Tuesday (Remembrance Day) ,
TEST on Wednesday so.. STUDY PEOPLE!

That's all for today's class,
your next scribe is christine d.

Bye :)

Scribe Time

Hi this is benofschool, and I'll be your scribe for today...

We started off correcting chapter 11.2 Study Guide. So here are the answers:

enter, leave, external, conservation of energy, form, constant, created, destroyed, mechanical, decrease, simple harmonic, potential, kinetic, potential, kinetic, increases , decreases , friction , thermal

Here are the answers for the second paragraph:
shape, potential, kinetic, all, conserved, some, other forms, conserved

Now we corrected a couple of worksheets from the beginning of the week.
Here are the answers for Concept- Development Practice Page: Chapter 8: Energy

1)
W= Fd
W= 200N (4m)
W= 800J

2)
P = W/t
P = [200N(4m)]/4s
P = 200 watts

3)
P=W/t
P= 6000 watts or 6kw

4) 16nore (IGNORE :P)

5) 10 m/s of all of the cases. Apply trajectory formula to answer this question.

6) Block A wil reach the bottom of the incline first because of the incline's shorter distance.

7) 100J, 75J, 25J

8) 10 m/s for Points B, D, and E. Max Speed at Point C

9) Yes there will be a change in wind speed because the windmills will take some of the wind's kinetic energy.

That was it for that work sheet. There was one more. Diagram Skills Section 5-3.

1a) 0 J

b) E_p = mgh

c) E_k = (1/2)mv²

d) E = mgh_A - mgh_B

2a) 0 m/s

b)v= sqrt(2E_k/m)

3) First Column: All 0
Second Column: All 19110J
Third Column: 9555J, 12740J, 15925J, 3185J, 6370J
Fourth Column: 9555J, 6370J, 3185J, 15925J, 12740J
Fifth Column: 17m/s, 19.8m/s, 22.1m/s, 9.9m/s, 14m/s

4)The values are equal.

After that we took a look at our Work and Energy Booklet and learned about spring energy and the potential energy of the spring otherwise known as HOOKE'S LAW.

The formula for Hooke's Law is F = kx where F is the force, k is the spring constant, and x is displacement of the spring if it is stretched using the spring at normal length as the reference point. So now we can calculate the potential energy of the spring we are given a new formula derived from Hooke's Law and our good old area of a triangle of a Force vs Displacement graph.

W = area of a triangle
W = (1/2) F x
W = (1/2) k x x ---Now we substitute F for Hooke's Law
W = (1/2) kx²

Now we have 2 Potential energy formulae:

E_p = mgh
W = (1/2)kx²

We started working on a lab that involved Wind Up toys. This lab is due tomorrow I believe. Other than that just study up because the test on Circular Motion and Work and Energy will be on Wednesday November 12, 2008. The next scribe will be my best friend Rojuane...

Bye Bye

October 31, 2008

This Halloween in physics we did a Lab using a ramp, a cart, and a meter of floor, to measure potential energy and kinetic energy. With this lab we received a lab sheet which is due on Monday, We also received a chapter study guide which will be corrected in class.

The next to scribe is Benchmen.