September 1, 2009-
Today in class we continued our focus on motion in one dimension. Mr. Rylander did a demonstration about displacement, which included how to calculate displacement, negative displacements, and he included an introduction to velocity. Then we began the Sonic Ranger lab experiments where we worked with motion sensors. For the lab, we had a set of graphs with time and position,and our goal was to figure out how to recreate those graphs with our own movements using speed and direction. Another word for displacement is change of position. This is calculated by finding the final distance and subtracting it by the initial distance. We learned that there is such a thing as negative displacement which was when he was walking backwards. We also learned how to calculate velocity which is the displacement over the final time subtracted by the initial time it took the object to get to the certain spot. This lesson was very easy to follow and I don't wish I could have learned it a different way.

September 2, 2009-
Today we started class with a QOD. The QOD included initial position, final position, velocity and displacement. This let us apply the skills we learned yesterday on our own. Once we were done with that we continued work on the Sonic Ranger Lab. During this lab we had to decipher time and motion graphs by using a motion detector to recreate the graph on the computer. There were eight graphs we needed to use, and for each one we had to figure out the speed and direction we needed in order to make the graphs. After we all finished up part 1 of the Sonic Ranger Lab, Mr. Rylander had us apply ours skill from the Sonic Ranger lab by drawing position vs. time graphs and graphing out his motions. This was good practice and helped to see a visual.To top for a busy and eventful class he ended the day with a fascinating demo dealing with patterns in nature that everyone enjoyed!

September 3, 2009-
In class today we had a QOD, which was on yesterdays QOD. The first was asking what they did wrong in the problem worked, and the second was the answer they should have gotten (which was 1.5m/s, external image latex2png.2.php?z=100&eq=v%3D%20%5Cfrac%7B%5CDelta%20d%7D%7B%5CDelta%20t%7D external image latex2png.2.php?z=100&eq=v%3D%5Cfrac%7B8m-2m%7D%7B4s-0s%7D external image latex2png.2.php?z=100&eq=v%3D%5Cfrac%7B6m%7D%7B4s%7Dexternal image latex2png.2.php?z=100&eq=v%3D1.5m%2Fs). After the QOD we were told to start Sonic Ranger Lab part 2 which was dealing with velocity vs time graphs. We used motion detectors to replicate what we had done yesterday and then graph four of them in our journals. At each graph you had to compare the graph of position vs. time and velocity vs. time. The final challenge was to make the cart go fast, then stop, and then slowly move back to the motion detector. We finished the lab in class, but you still have to write the conclusion using quantitative connections (like external image latex2png.2.php?z=100&eq=v%3D%20%5Cfrac%7B%5CDelta%20d%7D%7B%5CDelta%20t%7D) and the whole lab is due tuesday when Mr. Rylander collects our journals.
The Sonic Ranger Lab helped us be able to see the contrasts between velocity and time-velocity is a very commonly misplaced misnumber for Speed-however they are very distinct things. Velocity takes into account things like displacement, where as speed is more of just a raw estimate. The QOD was a mistake that a student had made during the previous day, not some fabrication. In the second part of the sonic ranger lab, we used cars instead of humans, however they were only representative-there was no quantifiable difference.

September 4, 2009-
In class on Friday, we didn't start with a QOD because we did it at the end of class. We had 10-15 minutes to finish collecting data on the Sonic Ranger Lab Part 2. If people were finished collecting data and writing observations, they could start writing the reflection/conclusion based on the "Constructing Evidence-Based Explanations" sheet. This handout explained how to write conclusions for labs. You have to make a claim, support that claim with evidence, and then provide reasoning that connects the evidence to that claim.
Then, we went through a worksheet together as a class and it was meant to help us make connections for our conclusions. We have learned how to interpret position v. time graphs and velocity v. time graphs separately, but we learned two things that connect the graphs together. First, the slope of the line on the position v. time graph is equal to the velocity. Second, the area under the velocity v. time graph line is the displacement.
After learning about the connections between both graphs, we were assigned a project. This project will be related to the position v. time and velocity v. time graphs. The speedometer project will cause you to go on a trip for at least 5 minutes and record your mileage, during the trip. Right after we finished talking about the speedometer project, we were given the QOD.
B, P-T graph is shown for the QOD. Your job was to determine which V-T graph corresponds with the P-T graph. Since on the P-T graph there is a slight slope which is positive which corresponds to the V-T graph where the velocity is balanced. Then the P-T graph slowly goes on a constant rate which causes the V-T graph to directly go to 0 and not change in velocity. Then on the P-T graph a parabola forms which drops in a high rate. So the only graph which can correspond to the P-T is graph B.

September 10, 2009

Today in class, there was no QOD. We were given back our quizzes that we took on wednesday. We went over every question that was on it with Mr. Rylander. He explained to us that number 5 was one of the hardest questions on the quiz because many people leave the answer as a positive and forget that the slope is actually going backwards which means its suppose to be negative. Here are the answers to the quiz: . After we went over the quiz as a class, we were then given back our journals that we turned in on wednesday. Mr. Rylander pointed some good things out in some of our lab conclusions. When we finished looking over those, we finished up class by taking notes on a demo Mr. Rylander explained. During this demo, the whole class took notes and drew out a diagram Mr. Rylander drew on the board. He asked us two questions about the diagram:
1.) What was the average velocity of the ball down the ramp?
2.) Where did it have that exact velocity? Here is a picture of what the diagram looked like:
DSC00183.JPGexternal image latex2png.2.php?z=100&eq=%5Cfrac%7B%5Cupsilon%20t_b%20%7D%7Bt_b%20%7D%3D%20%5Cfrac%7B100cm%7D%7B2sec%7D%3D%20%5Cfrac%7B50cm%7D%7B1sec%7D%0D%0A
The answer to number one: 50 cm/s. To get the answer, you do 100 cm over 2 seconds. The answer to number two: 25cm which is 1/4 of the total way to the bottom of the ramp. We knew this because the speed at the top of the ramp was 0cm/s, and the speed at the botom of the ramp was 100 cm/s. It made sense that the 25cm mark would be 50 cm/s.

September 11, 2009

In class on Friday we started off with a QOD. Our graded Speedometer Projects were also handed back to us. After everyone was finished working on the QOD, we reviewed the ball diagram that we drew the day before. The majority of us thought that the ball would have the velocity of 50cm/s right in the middle of the ramp. To find out if this was true, Mr. Rylander had us clap right when he let go of the ball, right when the ball reached the 1/2 way mark on the ramp, and right when the ball hit the table. If our claps were evenly timed out, we would know that the 1/2 way mark was the 50cm/s mark. We realized that our claps were rushed at the end and weren't even spaced. This was because as the ball rolled down the ramp, the speed picked up. We figured out we had to clap earlier. This led us to the conclusion that the 50cm/s mark was 1/4 of the way down the ramp.
This demonstration led up to the new material we had to learn. Everyone then took notes and we learned some new equations:
equation1.png

This is the equation to find the average velocity. We already knew this equation, but it is still important to know.


equation2.png
This equation was totally new. The "a" stands for acceleration. We then looked back at the ball diagram and realized the acceleration is not the same thing as velocity. In the ball demo, we learned that every second, the ball went 50 cm/s faster than the second before.

equation3.png
We then learned this equation. This equation is used to find out how fast an object is going.

equation4.pngThis equation is used when you want to know how far an object has traveled. To get this equation we had to use algebra in order to simplify as much as possible.

equation5.pngThis was the last and final equation. Again we used algebra to simplify the equation. Mr. Rylander ran out of time fully explaining this one, but I'm sure we will go over all of these once again in class on Monday.

September 14, 2009

Today in class we started off with the QOD. As we were working on that, we reviewed the five new equations we learned last Friday (see 9/11). In the QOD, we had to first solve for the acceleration of the police car. Then, in the second part, we had to find how far it traveled (Displacement). We concluded that there were two ways in finding the total distance traveled, by using the equation, and by using the Velocity/ Time Graph. Then, we concluded that the Equation to solve for Displacement was the same as finding the area of a rectangle plus that of a triangle.
After the QOD, We received a packet called Motion in 1-D solving practice. Mr. Rylander explained the steps in solving the problem so it was easier to understand. We worked in our lab groups until the end of class and we were instructed to finish up to problem 4 for homework. In these problems we learned that first we have to sketch the problem out to visually see what it looked like. Then, we had to find the knowns and unknowns of the problem. Based on finding the knowns and unknowns, we set up an equation and then solved it.

Problem 4 used two different equations. The first was the last equation that we learnedequation5.png
and the second equation3.png. First we had to solve for a and then plugged a into the second equation.
Finally we ended with 6.25 seconds as the final time.

September 16, 2009

Today in class we started off my going over the answers to some practice problems. We received a packet a couple days ago, which gave us different scenarios using the different equations we learned. Here was the solution sheet we received to check our answers Practice Problems Solutions . We then broke off into our lab groups and worked on today's QOD 9-16-09 . We were asked to find the total displacement of the car moving before it stops. The car stops because a child suddenly runs on the road. The start solving this problem, we were told to draw a sketch of the situation a our first step. This is the sketch our lab group came up with to visual the situation. After the sketch (below), we realized that this is a two step problem because you need to find the displacement when there was no acceleration, and when there was an acceleration due to the child. We then listed our knowns and unknowns from the problem. What we knew from this problem was the initial velocity, latex2png-5.2.php.png, the final velocity, latex2png-4.2.php.png, the acceleration ,latex2png.2.php.png, and the final time latex2png-3.2.php.png. Although the final velocity was not given in the problem, we claimed it to be latex2png-4.2.php.png, because the acceleration given was a negative acceleration. Also when the car stopped, it implies it is at rest; therefore, the final velocity is then recorded making it that. Our unknowns was the total displacement, what we're solving for. We then set up two equations, one for where the car was moving at a constant velocity latex2png-1.2.php.png, and one where the car slowed down and came to a stop, equation5.png. For the first one we chose this equation because for that part of the time there was no acceleration, therefore it is simply latex2png-1.2.php.png. For the second one, equation5.png, time is not really an important variable, therefore we looked at our knowns and unknowns and came to a conclusion this one contains the variable were looking for along with all the variables we already know. We then simply plugged in our knowns into the equations to find our unknown. After we plugged in our numbers we were given into teh two equations, we received answers of latex2png.2.php.png and latex2png-2.2.php.png. We then added them together to get the total displacement of latex2png-6.2.php.png. We did this because you were trying to find the total displacement from when the car started moving to when it stopped, which includes both parts of the drive.
Here is a quick sketch of our QOD.




Physics.jpg

After we all turned our QOD folders, Mr. Rylander introduced to us our next lab. This lab is called Acceleration Due to Gravity. Mr. Rylander explained how the famous physicist Galileo tried an experiment of dropping a single egg and dropping a dozne eggs and to find out which would hit the ground first. Well in our lab we are using different types of balls (i.e. tennis balls or rubber balls). Each lab group recieved one digital camera and is supposed to record one member in their group throwing a ball up and catching it using a meter stick so you can keep track of the scale of the ball. There was not much time to get through a whole lot with the lab, so most lab groups were able to mass the ball they were using and start to plan how they want to record the motion of the ball. This lab isn't due until Friday, so most groups will get most of their work done tomorrow and Friday in class.





September, 17, 2009

Today, we spent class working on the lab, Acceleration Due to Gravity. The goal of this lab is to find the acceleration of gravity for your given object and then compare your acceleration to that of groups of objects with a different mass. The conclusion must consist of how mass affects the acceleration of an object. To do this we picked a object (type of ball) and recorded its weight using a scale. Next we recorded videos of ourselves tossing a ball up against a yard stick. After, we used Logger Pro on the computer to make a velocity vs. time graph and finding the acceleration of the ball. The program gave us the tools necessary to make a graph out of our video. We did this by uploading the video, setting the correct measurements of the video, and clicking on the ball marking its path as it went up to the yard stick, then fell back down again. This created our graph, with velocity on the y axis and time on the x axis. To find the acceleration of the ball we used the formulaequation2.png (acceleration = change in velocity over change in time.) To find the change in velocity you have to subtract the initial velocity of the ball from the final velocity of the ball. The change in time is the amount of time elapsed. Each group must compare their acceleration and mass of their ball to their classmates.
Below is a graph which compares the mass and acceleration of each groups ball to other groups.
*ALL GROUPS: Please enter your data in the graph below :)!!!
Acceleration Due to Gravity

Group #
Mass of ball
Acceleration of Ball
1
.5g
-12.36m/s/s
2
1.85g
-10.3m/s/s
3
17g
-10.27m/s/s
4
.5g
-10.35 m/s/s
5
14g
-10.74m/s/s
6
14g
-10.74m/s/s
7
42.5g
-12 m/s/s
8
46g
-8m/s/s
9
10 grams
-9.533 m/s/s
10
46 grams
-8.78 m/s/s
11
287 grams
-9.934 m/s/s
12
2g
-10.69m/s/s

September 21, 2009-

Today in class we started out with the Question of the Day. This question was designed to help us prepare for the science portion of the ACT. It presented two experiments from data about styrofoam and iron objects and the accleration of them. We answered questions about the accleration from graphs and charts. After the question of the day, we looked at problems that had to do with dropping a ball and figuring out either velocity or the total distance that an object fell.

The first problem we did was finding how deep a well was after dropping a ball down it, you heard the ball hit after falling for 3 seconds.
To better understand this problem, we drew a sketch of someone dropping a ball down a well. Then we wrote down our knows and unknowns
DSCN0423.JPG

Knowns
Unknowns
ti= 0 s
tf= 3 s
vi= om/s
a= 9.8 m/s/s

vf= ?
displacement

Equation: equation3.png then equation5.png
equation4.png (Or you could use this one-step equation.)
The answer should be= 44.1 m.
- The second problem that we did was to find out how long it took a ball to fall off of the Sears Tower. As before, we sketched what the scenario might look like. then we talked about the knowns and unknowns again.

DSCN0424.JPG
Knowns
Unknowns
442 m
a= 9.8 m/s/s

the total time
Equation: equation4.png
the answer should be - 9.5 seconds.


  • A main idea that we learned from today is that there are many different ways you can solve these problems using different formulas, all of which will produce a correct answer.
  • We also learned that 9.8 m/s/s is the accleration for all falling objects on Earth.

September 22, 2009

Today we started class with our last QOD for this unit. The question asked us to find...

(a) The slope of the graphed line (Answer: Slope = -10m/s/s)
You find this becuase you have to pick two points on the graphed line and calculate the rise over run.

(b) What the slope represented (Answer: The slope represents the acceleration)
(Since the slope of the line was -10m/s/s the acceleration is also -10m/s/s -- this is the acceleration also because we concluded that all falling objects have the same acceleration of about -10m/s/s when air resistance is ignored).

(c) How long it took for the ball to reach its highest point (Answer: It took 5 seconds).
This is found by looking at the graph for the time at zero velocity (because zero velocity is when the ball was at itshighest point).

(d) How high the ball went (Answer: 125m)
To find this you find the area of the triangle above zero velocity. The equation we used to get the area wasexternal image latex2png.2.php?z=100&eq=A%3D%5Cfrac%7B1%7D%7B2%7Dbh
Then we plugged in 5 for b and 50 for h, which gave us 125m.


After the QOD, we reviewed the lab that was due at the end of class yesterday. Mr. Rylander talked about the main ideas that we should have understood from the lab. All in all, we learned that acceleration is not affected by the mass of an object. We also learned that gravity can't be changed based on how hard an object is thrown. After this, we got together with our lab partners and calculated our reaction times. We used rulers and realized that if we know the distance that were catching the ruler at, we should be able to determine the reaction time. With our partners, we each took 3 turns catching the ruler after our partner dropped it. Then we took the average of the 3 times. We converted the centimeters from the ruler into meters so that we could use an equation that we learned in class. To figure out the reaction time, we used the equation: equation4.png We use this equation because we know all of the components in this equation except for what we are solving for which is the final time (representing the reaction time). The homework that was assigned to us was to work on the webassign that is due on Thursday.
September 24, 2009

Today there was no QOD. The first thing we did was recieve a plan for the new lab: Water Balloon Drop Contest! In this lab the goal is to hit Mr. Rylander with a balloon by droping it off the bleachers. The lab prompt says that Mr. Rylander will move at a constant velocity, but will change his velocity in his three seperate trials. It is our job to figure out his acceleration and time him so when we drop the balloon it will inevitably splash Mr. Rylander. Mr. Rylander then let us go to work on develpoing an idea of how we could splash him. The class ended when Mr. Rylander left the class to talk about our strategies to splash him. Here are some of our ideas of what we needed to do.

1) Measure height and distance KNOWNS: UNKNOWN:
2) Find the velocity of the balloon and the runner Vi=0 deltaD=?
a=9.8m/s/s Vf=?
Ti=o Tf=?