9/6 Eroglu

                  At the beginning of class on the board it said to sit down to check homework. Coats-Haan passed out the answer keys to the Vector Addition 1 Homework and gave us some time to compare our answers with the ones on the keys and to correct our answers if some were wrong. The Vector Addition 1 Homework was assigned in order to add to our knowledge of adding collinear vectors together. One simply adds magnitudes of vectors together when both go in the same direction; one subtracts when the vectors go in opposite directions. After completely checking the homework, Coats-Haan commisioned me to pass out unit circle sheets, Kyle Armour to pass out Pairs Check - Vector Addition 11, and Jack Dombrowski to pass out Vector Addition Homework, which is the assigned homework for tonight.
                   During the distribution of the unit circle sheets, I accidentilly gave a group, which only needed three sheets, four sheets. After realizing this, I took one of the sheets back. We started with the unit circle sheet. Coats-Haan asked what the cosine and sine of 30 degrees were. I raised my hand; subsequently, I answered with radical three over 2 for cosine and one half for sine.
                    She then asked what the cosine and sine of 45 degrees were. Emily Chao answered with radical radical 2 over 2 for both.  Coats-Haan then illustrated how the cosine and sine of an angle on the unit circle are really just 2 vectors that add up to make a larger one. Coats-Haan next gave a powerpoint presentation on the ROXY method. This is a method used to calculate the magnitude and direction of the resultant if the two vectors used were neither collinear nor formed a right angle.
                      Through her presentation, I learned that one must break each vector into x and y components. It is useful to make a table. X is equal to the magnitude multiplied by the cosine of the direction; y is equal to the magnitude multiplied by the sine of the direction. This is done for each vector. The X component of one vector is added to the X component of the other.
                      The same thing is done for the y components. The combined sum of the the x components and the sum of the y components are then plugged into the pythagorean theorem. The answer is the magnitude of the resultant. Finally, one must take the inverse tangent of the y component over the x component(y/x) to find the direction of the resultant. If the resultant vector is in quadrant 1 nothing is done to the angle/direction, if in quadrant 2, 180 is added to the direction. If the resultant is in quadrant 3 180 is added to the direction and if the vector is in quadrant 4, 360 is added to the direction. After Coats-Haan finished showing us the ROXY method, we started to work on the Pairs Check - Vector Addition 2 work sheet.
                       By working together we got to number 4 before turning our sheets in and leaving for third period. By adding the x components of each vector to each other and by adding the y components of each vector to each other, the adding of collinear vectors is incorporated. When the pythagorean theorem is used by plugging in the sum of x components and the sum of y components, the right angle vector addition is displayed since a right angle is formed between the new x and y components.