CLASS+NOTES+-+DAILY+SUMMARY

= =


 * __CLASS NOTES__**

PLEASE POST DAILY NOTES HERE. You may also want to add interesting links, problem set solutions, etc. This page should provide all students will a good course summary.

SEPTEMBER 12 - Maria
Topic: Introduction Text Reference: None. See handouts Idea: An Introduction to SPH 4U 1. Couse Outline and Wiki 2. Syllabus 3. Taking Notes
 * Unit: DYNAMICS**

4. Group Work 5. Inquiry cube activity 6. TED Talk - [|Beauty and Truth in Physics]

SEPTEMBER 13 - Celton
Topic: Significant digits Text Reference: Appendix E - page 765 or see handout Idea: Significant digits and error
 * Unit: DYNAMICS**

1. Activity: The Art of Measurement


 * Unit: DYNAMICS**

Topic: Significant digits/Percent Deviation/Accuracy vs. Precision Text Reference: Pages 24 - 32. Questions #1-3, Pgs. 31-32 Idea: Significant Digits

1. All non-zero numbers are significant. ie. 123.234 has 6 s.d. 2. All zeros, between non-zeros are significant. ie. 120032.023 has 9 s.d. 3. Zeros after a decimal are significant. ie. 1.2000 has 5 s.d. (1.2 x 10 ^ -1) 4. Trailing zeros are not significant. ie. 12000 has 2 s.d. (1.2 x 10^4) 5. Leading zeros are not significant. ie. .000234 has 3 s.d. (2.34 x 10 ^ -4) 6. Counted numbers are infinitely significant.
 * __Significant Digits__**


 * Addition and Subtraction**
 * The answer rounds to the same number of decimal places as the lowest amount in the question.**

ie. 2.343 32.12 1234

1268.463

... Which Becomes ...

1268 (4 s.d. is the least precise number in the question)

Only round at the final answer
 * Always round to the even number when the last digit is 5***

ie. 26.5 ... Becomes ... 26 AND 27.5 ... Becomes ... 28


 * Always incorporate one extra digit from the accuracy of the measuring device*


 * Multiplication and Division**
 * The answer rounds to the same number of significant digits as the least precise number in the question**

ie. 2.35 x 2.7267 = 6.40|7 745 = 6.41

Accuracy - Comparing an experimental value to a known value, when you have the known value. - When calculating deviation, use Percent Error calculations.
 * __Accuracy vs. Precision__**

%Error = (|Accepted - Experimental| / Accepted) x 100

Precision - How repeatable the experiment is. How well you can repeat the same answer with the mesauring device that you have. ie. Reliability. - When calculating deviation, use Percent Variation calculations. Percent Variation is within a column of numbers.

%Variation = (|Highest experiment value - Lowest experiment value| / Average) x 100

2.53 m/s^2 ... to ... km/hr^2
 * __Conversions__**

Ratio Method:

2.53 m 1 km 3600s 3600s x x -- x --- = 32 788 km/hr^2 s^2 1000m 1hr 1hr = 32 800 km/hr^2

Fermi problems are questions that are extremely broad. In order to solve them, you must make assumptions regarding the topic of the question. You can solve it using the order: 1. What information are you given? 2. What are you asked to find? 3. Do you need an exact or approximate answer? 4. Is the answer reasonable? 5. Is there another way to solve the problem?
 * __Fermi Problems__**

An example of a Fermi problem is "How many piano tuners are there in Chicago?" (Review the sheet that was given regarding this specific Fermi problem)

Other examples can be found on this website: []

=**SEPTEMBER 16- Tasha**= Topic: Graphs Text Reference: Page 24 to 32 Idea: Information found in the graphs

~Slope of a d-t graph is the velocity of the object- a slope of 0 is not moving, a slope greater or less than 0 indicates acceleration. ~Slopes of tangents can be used to find the velocity at a specific point. ~Check out this video for a lesson---> []
 * __Distance vs. Time Graphs__**

~Area under a v-t graph is the distance an object has traveled ~Slope of a v-t graph is the acceleration of the object - a slope of 0 is uniform motion, a slope greater or less then 0 tells you the acceleration of the object. ~Check out this video for a lesson---> [] There are 3 parts, all about 3 minutes long!
 * __Velocity vs. Time Graphs__**

~This video explains how to turn a d-t graph to a v-t graph---> []

**SEPTEMBER 19 - Celton**
Topic: Kinematics Grade 11 review Text Reference: Page 10 - 12 (Good flow chart on page 12) Idea: Using the big 5 kinematics equations

Kinematics problems can be generally be solved using one of these equations:

PLUS d= v2*t - .5*a*(t^2)

When using these equations, we go by the following standard: The reference point = initial position The reference direction = initial direction The reference time frame = t0 By using this standard, we can omit the delta symbol in our equations, making life easier.

The proper form for solving an problem goes something like this: 1. Define reference point and direction. You can include a diagram such as: + --> [E] Which refers to that east is the positive direction. 2. State your known (given) variables. 3. State the variables you want to know. 4. State the equation you are going to use. 5. Evaluate. 6. Conclude, remember units **and direction if value is a vector!** Calculations need not show direction in forms other then (+) and (-), such as cardinal or polar directions. These must be included in #2 when you state your variables, and your conclusion!

Handbacks: Significant digits assignment Homework: Finish assign Graph Analysis Assignment (due Wednesday) + Study for Sigfig test (Tuesday)

**SEPTEMBER 20 - Brittany**
Today in class we did a quiz and watched a movie about the "power of ten" which was posted on the wiki by Maria. Don't forget to get a picture/explanation about the exhibit for our review of g.11 physics :) AND MAKE SURE YOUR ASSIGNMENT IS FINISHED!

**SEPTEMBER 21 - Monette**
Topic: Kinematics review Text Reference: Page 20 (Example 10) Idea: Applying the kinematics equations to situaitons

Today in class we solved a word problem involving kinematic equations similar to Example 10 on page 20 of the physics text book. No new assignments were given.

=**SEPTEMBER 23 - Tasha**= Topic: Kinematics Idea: Dual Body Problems

EXAMPLE:

Object A is moving at an initial speed of 10m/s with an acceleration of 1m/s^2. Object B is initially at rest and starts moving with an acceleration of 2m/s^2.

From this you know that da=10t+0.5t^2 and that db=t^2. You also know that da=db+50, so you can find the time that the objects meet: da=db+50 10t+0.5t^2=t^2+50 t^2-0.5t^2-10t+50=0 t^2-20+100=0 (t-10)^2=0 t=10

We also started our egg balancing today, this person is crazy! :P []

**SEPTEMBER 26 - Celton**
Topic: Uniform acceleration (cont) Text Reference: For uniform acceleration practice, refer to handout. Idea: Practice uniform acceleration problems and intro to CGPS!

1. We received our graphing assignment back and did a review of d-t graphs. Here are all the different types of d-t graphs, all of which were reviewed. We also discussed what two-body diagrams might look like on a d-t graph. The complete graph may look like any combinations of the curves above, but remember to fit your graph to reality. If two bodies collide/ stop when the meet, don't continue the curve afterwards, as there is no further displacement, even though mathematically and theoretically there is. For the purposes of the assignment (due Wednesday) draw the full curve, but only use solid for the actual motion, and dotted lines for the continued theoretical motion. Another example where this could occur is when an object is slowing down (accelerating in the opposite direction of its velocity) and comes to a full stop. For our purposes, generally we assume the objects is stopped, even though theoretically it would stop and continue on the direction of acceleration.

2. The second part of class introduced us to CGPS - Cooperative Group Problem Solving. [|Refer here] CGPS continued onto Sept. 27 lesson. We also received more uniform acceleration problems practice handout.

**September 27 - Cheryl**

 * Topic:** Kinematics
 * Idea:** Applying kinematics in the real world; physics really works!

Today we conducted an experiment/challenge with washers and string. Using kinematics equations such as d=vit+1/2at^2, all the groups were able to find the appropriate distances to space the washers on the string, and successfully "clinked" the washers in rhythm as they were dropped. It was both educational and exciting.


 * REMINDER: ASSIGNMENT DUE TOMORROW! FINISH IT!**

**September 30 - Alex**
Topic: Vector addition + Rocky Mountain Express Idea: How to add vectors using the tip-to-tail method for right-angle triangles and non right-angle triangles.

To add two vectors, simply lay them tip to tail. Touch one vectors tail with the other's tip while still maintaining their correct directions.

Then if the two vectors form a right-angle triangle with each other, use the Pythagorean theorem to find the magnitude of the resultant vector and the sin, cos, and tan functions to find the direction of the vector.

For non right-angle triangles, use either the cosine law or the sign law depending on which vector magnitudes and directions are given.

October 4 - Brittany
Topic: Vectors Idea: How to draw/calculate vectors with respects to frames of reference

(as per wikipedia) A **frame of reference** is how one knows if an object is moving. For example, when you see a ball roll down a street, you can tell the ball is moving because the frame of reference is the streets, whatever may be on the side of the roads or the Earth. All of these are a frame of reference. The most common frame of reference is Earth itself, even though it moves. This just means that objects motion is relative to its frame of reference.

Ex. 1 Train moving stright N at 10m/s. A person crosses the train eastward at 4m/s. Find the overall velocity of the person (they're walking across the train, from aisle to aisle) Step 1. Draw the vectors! Make sure to include a set of axis in every drawing! 2. Sketch the vectors onto the set of axis. Labeling them so that it vectors have names like this : T V L where the first letter (T) denotes the object, in this case the train. V is velocity and the second letter (in this case L) denotes the frame of reference, in this case the land. Another example would be P V L, where P is the plane and L is the land. The resulting vector should always be in reference to the land. **you just sub in the variables that fit to your vector drawing. 3. Depending on the triangle that is made you could use multiple equations to figure out the magnitude of the vector (i.e Pythagorean theorem for RAT's( Right Angle Triangles), cosine law for 2 sides and a contained angle, or sine law). Then use SOH CAH TOA to figure out the resulting angle if needed.

Here's a really cool video about frames of references and the objects relativity. It's a little long but it's interesting ! []

October 5 - Monette
Topic: Vecors Idea: Combining two variables into a a vector

Example 2: Non-RATS vectors

Example 3- Vector incorporating distance and velocity

Homework: - Prepare for brief 2-3 min description on the exhibit your group has chosen to represent grade 11 physics terms. Due this Friday. (Upload picture of the exhibit if you haven't done so.) - Complete the Vectors Practice Problems worksheet so that you get practice and ensure you really understand vectors!

October 11 - Cheryl
Topic: Vectors Idea: More vector problems

Today, we completed a vector problem in class together: Then, we completed more vector problems in groups, which were handed in.

__Homework:__
The questions on the backside of the sheet (#1-5) are to be completed for Friday.

=OCTOBER 25TH - ISABELLA=

__FORCE ANALYSIS__

 * Fnet = F1 +F2 or F = Fy + Fx
 * For each problem, you must come up with an equation of your own based on the information given and what you need to find
 * In balanced forces, Fnet = 0
 * In **closed vector diagrams** all vectors must be added in a way which forms a proper vector diagram.
 * Closed vector diagrams are 1 method for analyzing static or constant speed situations
 * A 2nd method for analyzing forces are by using the components of the forces at an angle, where the sum of all forces in the perpendicular direction include the perpendicular components of these forces and the sum of all forces in the parallel direction include the parallel components of these forces.

=OCTOBER 26TH - ISABELLA=

__NEWTON'S 2ND LAW__

 * States that the sum of all forces is equal to the mass times the acceleration of an object
 * Acceleration in proportional to Fnet and inversely proportional to the mass
 * In determining the Normal Force or acceleration of an object, you MUST draw a FBD.
 * Next, divide the forces into parallel and perpendicular (using components for angles) and solve by noting which group of forces in balanced and which is unbalanced (accelerating).

__FRICTION__

 * Always opposes motion (acts in a negative direction)
 * Dependent on 2 things
 * 1) Hoe much object and surface over which the object is sliding are pressed together (Normal Force)
 * 2) Properties of the surface (µ)
 * Therefore: Ffr = µFn

=**October 28th- Allie Martino**= we went on a field trip to U of T so here's an interesting video http://www.youtube.com/watch?v=ZP6_vXus0F4&feature=relmfu

Notes by Rachael Kitchen
 * __ November 1, 2011 __**

Handouts:
 * Zip-Line Challenge
 * **DUE Nov 22nd**
 * Newton’s Third Law Sample Questions
 * Intro to pulley problems
 * Went through questions 1-5 as a class
 * Last question on the back of the handout is a challenge question for tomorrow

__**November 2, 2011**__ Notes by Allie Martino

handouts
 * newton's third law handout with a pulley questions

build airplanes

=**November 4, 2011**= Notes by Allie Martino

Intro to circular motion worksheet and experiment

Notes by Rachael Kitchen
 * __ November 8, 2011 __**

Continuation of Circular Motion: Notes below with examples Handout: New question sheet, some are challenges

__**November 9th - Ellen**__

Universal Gravitation

Overview:
 * Everything has gravity on everything.
 * This force gravity can be calculated mathematically.
 * It can be applied to our free body diagrams, and applied to new settings such as outer space.
 * It can also be added to free body diagrams in a non-downward direction. (such as the gravity you and your computer are currently having on each other.)

Key Ideas:
 * Fg = mg near the earth's surface
 * Farther away from the earth's surface, Fg decreases
 * Fg is proportional to 1/r^2, where r is the distance from the centre of one body to the centre of the other (inverse square law)

Key Formula: ...Where:
 * //F// is the force the two objects exert on each other (must be equal according to newton's 3rd law)
 * //m1// and //m2// are the masses of the 2 things in the problem;
 * //G// is the universal gravitational constant, 6.67x10^-11,
 * and //r// is the distance from centre to centre of the two objects.

Useful Constants:
 * Mass of the Earth: 5.97 x 10^24 kg
 * Radius of the Earth: 6.4 x 10^6 m
 * Mass of the Moon: 7.4 x 10^5 kg
 * Radius of the Moon: 1.7 x 10^5 m

Don't Forget...
 * __...To measure radius from centre to centre__. This can sometimes mean adding the radius of the earth to the distance of the earth's surface to a satellite, etc.
 * It can be helpful to __rearrange formulas in terms of units__ before plugging in numbers.

Textbook Problems:
 * p. 111 # 5-7

Quote of the Class: //"In ten years you can think that no matter where you are, I'm having a gravitational pull on you."// -Maria

Notes by Rachael Kitchen
 * __ November 15, 2011 __**

Electricity and Gravity: Notes below with examples Handout: New question sheet



=__MOMENTUM 1-D__= -no lost in kinetic energy -> conservation of kinetic energy -conservation of momentum (C of M)
 * November 21, 2011** by Monette Tam
 * Elastic collisions:**

-lost in kinetic energy (energy not conserved) -conservation of momentum (C of M) -in perfectly inelastic collisions, the objects colliding stick together after collision
 * Inelastic collisions:**

-initial total amount of momentum equals to final total amount of momentum -assume closed system
 * Conservation of Momentum:**
 * -**vector quantities for speed

//Note: the dash at the top ( ' ) represents prime or the second speed for the same object// Equation: Ptotal = Ptotal ' P1 + P2 = P1 ' + P2 ' m1v1 + m2v2 = m1v1 ' + m2v2 ' //[Note: the v (speed) is a vector quantity meaning you must decide which direction is positive and use positive/negative values accordingly]//

If the product is 100%, it means it's an elastic collision.
 * Energy Retained:**

%E kinetic retained = ( ΣE ' / ΣE ) x 100%

//Examples will be posted later!//

- Testing the zipline challenge tomorrow!
 * Reminders:**


 * December 12, 2011** Erind Alushaj
 * Light- a Historical Perspective Powerpoint**
 * What is Light?**
 * Ancient Greeks: Pythagoreans--Particle
 * Ancient Greeks: Empedocles--Wave
 * 1685: Huygens--Wave
 * 1704: Newton--Particle
 * 1804: Young--Wave
 * 1905: Einstein--Particle
 * 1924: Bohr-- Wave-Particle Duality

An educated guess about the structure of something based on properties, to predict behaviours and believed to be true until new information becomes available. Light is difficult to study since it travels at high speeds and cannot be directly absorbed.
 * What is a scientific model?**


 * Properties of light**
 * Rectilinear Propagation
 * Reflection (regular and diffuse)
 * Refraction
 * Partial Reflection
 * Snell's Law
 * Increased distance is proportional to decreased intensity
 * Light has energy
 * Dispersion (white light seperates to its component colours)


 * Models of Light**
 * 1) Particle
 * 2) Wave
 * 3) Wave-Particle Duality
 * 4) Electromagnetic Wave

Newton proposed that light consisted of streams of tiny particles. Light is massless, travels at very high speeds and carries kinetic energy. Light of the same colour has identical particles and spreads out in uniform distribution from the source. Light undergoes perfectly elastic collisions, follows the inversre square law and travels faster in a denser medium. Different colours have different masses and amounts of energy. (red has more mass than blue) Light travels very fast and travels in straight lines. Due to perfectly elastic collisions the angle of incidence is equal to the angle of reflection.
 * Particle Model**

Experimentation with photographic paper.

Explains:
 * December 13, 2011** Erind
 * Particle Model**
 * Reflection
 * Rectilinear Propagation
 * Dispersion (each particle has a different mass and different colour as a result)
 * Refraction

Does not Explain:
 * Partial Reflection
 * Polarization

Predicts:
 * Using Snell's Law the speed of light in water was determined to be 4.2*10^8 m/s

Properties: Transverse wave: particles move perpendicular to energy emission
 * Wave model**: vibration transmitting energy through a medium

Longitudinal wave: particles move parallel to energy emission

Constructive Destructive
 * Interference**
 * [[image:thescienceclassroom/destructive_interference.jpg width="234" height="241" caption="Destructive Iterference, courtesy of http://obergscience.com/page3.htm"]] ||

Wave Model and Ripple Tank SImulations Read pg 538 -543 Read pg. 500 - 507
 * December 14, 2011** Erind Alushaj

Follow the Ripple Tank Simulator link in the course syllabus. Carry out all the investigations in the **Ripple Tank Investigation** handout. The Double Slit and Single Slit Interference Equations sheet was handed out along with the Snell's Law sheet.


 * Snell's Law**



The wave model of light can determine the speed of light in a medium; which the particle model could not determine.
 * n= sinƟ1/ sinƟ2 = λ1 / λ2 = v1/ v2**