10/26 Shah

On this lovely morning of October 26, 2011, we started our day in 2^nd period Honors Physics by turning in the Aristocracy questions worksheet and checking the questions from the book (page 155 #1-10). Then we began to take notes on relative motion. The notes were:

• Reference Frame
• Reference frame—an object that is assumed stationary that is used to analyze the motion of other objects
• This is like when sometimes you are waiting at a traffic light and the car next to you starts moving, so you slam on the brakes just to realize that you were never moving to begin with. Of course, Coats-Haan and I were the only ones in class who have done that.
• No object is truly stationary
• The Earth is the most commonly used reference frame.
• Mathematical Perspective
• (there was a picture of triangle ABC with
• The 1^st letter is where the object ends.
• D_CB & D_AC are vectors with heads and tails, so…
• D_AB = D_AC + D_CB
• Remember, the pattern always stays the same: A is in the beginning, B is at the end, and C disappears.
• This also follows the pattern that if you dived through by Δt, you get…
• v_AC= v_AB + v_BC
• Also, note that v_AB = -v_BA
• Planes
• Tailwind—when the plane flies in the direction of the wind
• Headwind—when the plane flies directly into the wind

As we continued to the pair checks, Coats-Haan mentioned how she wanted to be like Chris and that she sounded like Sonny today. Then we started what Coats-Haan consider one of the toughest pair checks we will do all year. We spent the rest of class attempting to finish it, but almost no group finished. We will spend time tomorrow in class finishing it.

For homework, we need to fill out the HAC sheet, find out blue sheets and fill those out for extra credit, and do #47-57 on page 84 of the book. Also, you may want to get a head start on both the non-linear test review and the 1st quarter review packet, which are both due Friday.

QOD: The magnitude of the ground speed is greater than the magnitude of the air speed. When we drew a vector of the velocities, we see the component vectors (air speed and wind vectors) cross to form a right angle, so the resultant vector (ground speed vector) would be the hypotenuse of the triangle. The hypotenuse of the triangle is always longer than either leg, and since the ground speed vector is the hypotenuse while the air speed vector is a leg, the ground speed vector will be greater than the air speed.

P.S. I don't know why the post is highlighted in white against the green background. I don't know what I'm doing wrong or how to fix it, but it's really bothering me. Sorry.