Saturday, June 30, 2007
Vectors
Getting the Resultant Vector Graphically
- As Mr. Mendoza taught us, we should draw first the North-South, East-West arrows as directions.
- After doing that, get the vectors. Scaling is a way to save space and it makes it easy for us to get the resultant vector. Several pieces of paper will be consumed if we do not scale.
- Specify the origin where the the first arrow will be drawn.
- Draw the first vector using an arrow containing an arrow head and tail. Connect the end of the second vector to the arrow head of the first vector. Do the same procedure to the succeding vectors. It is necessary to place the measure of the angle and the diretion to avoid pitfalls.
- Connect the arrow head to the tail of the very first arrow [which is located at the origin], and that will give you the resultant vector. Measure that.
- Make the necessary convertions to return to the origin values.
I wanted to learn at 10:27 AM.
Friday, June 29, 2007
Lesson Number One
The Mnemonics SOH CAH TOA are very important in determining the sides of a right triangle when the Pythagorean Theorem can not be applied.
If you know the value of one of the two non-right angles in a right triangle, and the length of one of the sides, you can determine the lengths of the other two sides using:
- SOH (sinq = o/h)
- CAH (cosq = a/h)
- TOA (tanq = o/a)

+] where
q stands for theta [the required angle to be found], where "o" stands for the side of the triangle opposite to the known angle, "a" stands for the side of the triangle adjacent to the known angle, and "h" stands for the hypotenuse of the triangle.
To avoid mistakes, follow these guidelines (as learned from our Trigonometry class):
+] the adjacent and opposite sides are always shorter in length than the hypotenuse.
+] the sine and cosine functions vary in value between zero and one (they are never larger, and come out positive if the angle is considered positive).
+] the sine of zero degrees is zero; the sine of ninety degrees is one.
+] the cosine of zero degrees is one; the cosine of ninety degrees is zero.
I wanted to learn at 10:53 PM.
Sunday, June 10, 2007
First Week of Physics Class
The first day of our Physics class turned out to be good. The first week of Physics class wasn’t boring.
We met out Physics subject teacher, Mr. Mendoza. He was nice, actually and his policies are not bad after all. He isn’t that strict. He lets his sleepy students get their siesta on his subject but you wouldn’t learn anything if that happens.
He lets us take our first quiz at home because there was no time left after he has given the set of questions. The topic of the quiz was SOHCAHTOA. They were formulae which help us find the different parts of a right triangle beside from the Pythagorean Theorem.
Our first activity done in school was to find the vector scale graphically. I was at that time so I didn’t absorb the activity that well. How I wish I could learn that easy.
I wanted to learn at 10:27 PM.