December 14 ,2010 - Starting to Going Over Lesson 8

Today in class we started by finishing watching Mythbusters.
After we finished watching the video, we went over lesson 8.
8.1 a) We said that the Americans With Disabilities Act is concerned with the steepness of accessibility ramps because there shouldn't be too much force (not work) needed to go up the ramps. It isn't about work because the amount of work stays the same no matter how steep the ramp is. This is because when the ramp becomes less steep, there is less force but the distance increases.
b) since the ratio for the height and width of the ramp was 1:12, I said that possible ramps are 3m by 36m, 5m by 60m, and 12m by 114m.
c)I said that ramp "iii" fits the requirement.
In class we learned that you can find how much force needs to be applied to something by doing (Mass * 10). This is only true with kilograms so if it is in any other units, it must be converted into kilograms.
d)
i) To find out how much work is done on that ramp, we needed to know that Force * Displacement = Work. Using this rule, Mass * 10 = Force, we found out that we would need to apply 200N. The height of the ramp was 2meters so the displacement is 2m. By doing 200N * 2, we found out that it would take us 400J of work to push a wheelchair up the ramp.
Class ended so we did not go over the rest of problem d)

I was still confused about why we take the height of the ramp for displacement and not how much you traveled/moved the wheelchair

-AT

Decmber 10, 2010 Period 2

We had a sub today, so nothing really happened. We worked on section 8 in the energy activites packet and we have to finish it for homework.
http://www.npsd.k12.nj.us/20222069133223760/blank/browse.asp?A=383&BMDRN=2000&BCOB=0&C=59194 here is the link to the page for Energy Activities. Its on the bottom of the page.
GS

energy activity sheet

Today in class when we went over the energy Activity Sheet we had for homework. For the first problem The number sentence was 3J +2J=5J. My initial state was You're falling down a mountain(halfway down) and my final state was you're moving really fast at the bottom of the mountain. On my bar chart i had 3J for kinetic energy and 2J for gravitational potential energy (before side) and 5J for kinetic energy on the after side.

The second problem's number sentence was 4J+(-2)=1+1. My initial state was a cart coming toward me and then i pushed it away from me and its about to fall off . My final state was The cart is falling down the mountain about to hit the ground. For my bar chart, i put 4j of energy for gravitational potential energy and -2 work being done(before side). I put 1J for kinetic energy and 1J for gravitational on the after side.

The third problem's number sentence was 200J+800J=500J+500J.My initial state was you jump off a cliff, moving fast,you're 4/5 of the way down.The Final state is you're half way down, moving fast. For my bar chart, i put 200J for kinetic energy and 800j for gravitational potenial energy (before side). Then i put 500J for kinetic energy and 500J for gravitational energy on the after side.

AR

towards the end of class Mr.Finley asked the question why does a pendulum swing back to its original height? Clarie answered that its because nothing does work. She also mentioned that when the pendulum reaches its highest point it has the same amount of energy it started with.

Tuesdays Blog

At the beginning of class, I asked a question about what constant and conserved energy was. Mr.Finley said that consistant energy was when the amount of energy does not change, but the type of energy changed. Conserved energy is when energy changes in a predictable way. The quiz tommorow will be on bar charts, number sentences, and energy. He said to just remember how to make bar charts.Mr. Finley told us to discuss about a problem where a box went from the ground to high up in the air. He said to say which process will require the most amount of energy. A crane lifting the box, a person pushing the box on a slanted board, or a person pushing it on a spiral staircase. We said that the spiral stair case will require the most energy. we had to draw a bar chart for all of the sceneareos. Mr. Finley said all of the situations started out with no energy. It turns out that all of them had the same amount of energy at the end. They all had the same amount of work as well. We discussed why we might want a spiral stair case. We said that the spiral the 50J of energy will be used in a longer amount of time, makeing it easier. For the crane, it is a short distance, but it will be much harder to lift it straight up. We discussed that a pengulem would be dropped at a height. Where would it be on the other side. We also said to say what would happen if there was a bar in the way. We said that the pengulem will go the same height as it was before. If there was a bar in the way, we said that it will go half of what it would normally go. Remember to study!

MP

Monday, December 6th: Skateboard Problem

Today, in class, I began working on the skateboard problem. For the skateboard problem, the first part is to design a skate park for the skater to skate on. After a few minutes of designing, I designed a skate park like this:

Afterwards, I had to answer a few questions about the skater/skatepark. Here are my questions and answers:

a) Draw a picture of your track.

(shown above.)

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Place the skateboarder on the track and observe the motion. You can investigate further by changing the skate or you can scroll down and adjust the fiction. Choose two different situations from the simulation that you can analyze and then share with the class.

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1. My first situation is on Earth, with the PhET skater. The track is my original track shown above, and the friction is none. I observed that the skater keeps on going at a consistent speed and it pauses for the same amount of time when it reaches the ends of the track every single time.

2. My second situation was using a bulldog on the Moon. The track is still my original track, but the friction is medium. I observed that the bulldog wasn't able to move as fast; in fact it couldn't even go through the loop because of the friction. Things on the moon are supposed to be lighter, so friction can really slow someone down.

b) Describe or draw your chosen initial and final states

initial final

c) Include your choice of a systems

My choice of the system is the Earth and the skater.

d) Create three different representations (i.e. picture, bar chart, force/motion diagrams, number statement, graphs, etc) to demonstrate the changes that occurred during the process.

40J + 20J = 20J + 40J

e) Is the skateboarding situation realistic in terms of the physics and energy?

Yes, because the more friction there is, the harder it is to move in real life. Not any of the things programmed into this game have violated the laws of physics.

That is about all we did in class today. If this wasn't finished in class, it was finished for homework.

- J.L.

Friday, December 3 - HW Review & Elephant Project

Today we went over the homework and had a class disscussion. The homework was to make problems that related to the 3 number statements given. You also had to describe the proccesses of energy conservation and the constant processes. Last, you had to draw a bar chart and solve the problem. When we went over the homework as a class, and we realized how to follow the number statements that were given to us and accurately make a problem that relates to it without stating what happens prior to what you're given.

Then, we went back with our groups to work on the elephant project. We started the elephant project two days ago when we watched a video to start us off. The video was about an elephant that steps onto a trampoline. It shows the elephant walking up the steps, and starting to jump on the trampoline and jumping on it. Mr. Finley gave us a task to find 5 things that related to energy from the video, draw the intial and final states, bar charts, and number sentences. There was also an additional question which is: "Is the elephant situation realistic in terms of physics and energy?

You can watch the video at:

http://www.youtube.com/watch?v=TK27aknWVI4.


A.L.

Today we worked on the elephant promblem. In the elephant problem we saw a elephant jump on a trampolene and do flip. He asked us 5 questions. 1. Write about 5 different things in the video that relate to energy. We said walking to climbing stairs. Stairs to trampoline. standing on trampoline to jumping on it. At the peak of height falling. From trampoline to walking. 2. Describe or draw intial and final states. 3. Include your choose of system. We said The elephant, trampoline, and earth. 4. Create three diffrent representation( picture, bar chart, number statement.) to demonstrate the changes that occured during the process.5. Is the elephant situation realistic in terms of the physics and energy? Explain.
If you want to see the video go to youtube.com and type in elephant jumping on trampoline
Then we went to a website(colorado.edu) and played a game energy skate park. It was a person on a ramp going back and fourth.

-MM