September 14, 2012Andrew Wang

LESSON SUMMARY

-There weren’t many notes we had to take during this class. But, here is a summary of what we did.

Homework check First off, Ms. Evans checked our homework and took up questions #7 and #13. For question 7, she gave us a smiley-face stamp if we finished it, and she thoroughly explained question #13. We created position-time graphs for question #13 on the graph paper that she gave us.

Mine looked like this:

Super-Fun Activity (Not very important for notes) Afterwards, we did a fun activity in groups of four. We were given paper cubes with three numbers on each side and a physics term. Our task was to find both the term and numbers on one side which was placed face down. The rules of this activity were:

-Do not touch the cube (Flip over, move, poke)-Find both the term and the three numbers on the face-down side-When you think you have the answer, write it down on a whiteboard-Do not share your answer with anybody else (because the face-down side was the same for each group)

The given sides of the cube were as follows: -Scalar: (6,4,2) (opposite side of Vector)-Vector: (6,4,2)-Speed: (8,3,2) (opposite side of Velocity)-Velocity: (5,5,3)-Distance: (12,5,3)-??????? (opposite of distance)

Looking at the terms made my group realize that the sides opposite to each other are scalar and vector terms. For example,

-Scalar/Vector (self explanatory)-Speed = v /Velocity = v

From this, we realized that since distance is a scalar and is represented as ‘d’, the term on the missing side must have been d , or displacement. We then examined the numbers. We noticed that all the numbers on the sides add up to the same number the opposite side adds up to. For example, Speed (8,3,2) adds up to 13, and its opposite side Velocity (5,5,3) adds up to 13 as well. We came up with the fact that the three numbers of the unknown side must add up to 20. We then noticed that the first number is the number of letters of the term on the opposite side. For example, Speed has 5 letters and the first number on its opposite side, Velocity. Velocity has 8 letters, which is the first number for the Speed side. We figured out that the second and third numbers are the number of consonants and vowels on each side respectively (not opposite side).

In the end, our conclusion was that the unknown side was Displacement: (8,8,4) -The first number represented the number of letters in the word “Distance” (8)-The second number represented the number of consonants in the word “Displacement” (8)-The third number represented the number of vowels in the word “Displacement” (4)

Interpreting Velocity Time Graphs Practice For the rest of the period, we worked on a sheet determining what happens to a car on a velocity-time graph. Here is the graph:

Looking at the graph, we first had to record the time interval for each region (A, B, C…) and then had to determine three things:

-Is it accelerating? (Answer in +/0/-)-What’s its velocity? (Answer in +/0/-)-Is it speeding up, slowing down or is it at a constant speed?

There was a process for determining each one. -Acceleration: If the line is going upwards, the acceleration is positive. If it is going in a horizontal line, it is

0. If the line is going downwards, it is a negative acceleration.-Velocity: Since it IS a velocity-time graph, velocity was simply determined by whether or not the line was

above zero (0m/s). Positive means that it is above zero, 0 is if it is at zero and negative if it is below.-Speeding up, slowing down, or constant speed: When the car speeds up, the line goes upwards. If it is

constant, it is a horizontal line. If it slows down, the line goes downwards. HOWEVER, that is providing if they are all above the 0m/s line. Since it is a velocity-time graph, going under the 0m/s line means that the car is getting faster in the opposite direction.

Here is the finished chart:

There was also homework on the back side of this sheet. (Only the first half of the sheet though)

We were told to use this formula to find out the answers of the homework.

Slope Slope-displacement-time velocity-time acceleration-time

OR Area Area-displacement-time velocity-time acceleration-time