November 30, 2010

Today in class, the first thing we had to finish up was to go over the ski problems and to make sure that you made the bar charts for it. Bar charts should look like this.

Rasing the Bar packet must be done and you should almost be done with the Energy packet.

You also have to go over the homework that is due today and start making bar charts for all of the problems.

Energy Packet

1. The first problem was that Jessica stands on the 1st floor of the elevator. The door closes and she goes up to the 4th floor. Jessica and earth are in the system.

a.) Jessica, Earth, and Elevator

b.) Initial is when she is on the 1st floor. Final is when she is on the 4th floor.

c.) Creat own work-energy bar chart

2. Alan's Solution

a.) We agree with Alan and his charts are correct and so are his answers.

b.) The chart helps him see the changes from start to end and the amount of work done.

c.) They show the amount of work and energy in the system.

d.) He found out that displacement * force = work and he found the lengths of the bars.

3. 4.5 Reason

a.) The work and the final energy would be split in half.

b.) She would still have GP energy but less than if at the top. She would not have kinetic because the elevator moves at a constant rate.

c.) 0+1000J=1000J

That's all we got done in class.

-Yam

Class on 11/24

In the beginning of class, he told us that:

we are going to start a group project on Tuesday. The bar chart packet must be done by then.

We had everyone break up into their groups as usual, and the "skier people" looked at a PowerPoint presentation on his laptop, and we need to remember some of it for the homework.

The homework for the "elevator problem people" is to do the skier problem, and for the people like my group, "the skier problem people" is to correct and explain any mistakes you made using the PowerPoint presentation that we looked at in class.

I have a question for everyone out there: for the system for the skier problem, why is the mountain not in the system?

And, if you don't get how to make bar charts for the skier, I have a hint; he tells you what the system is in one of the old hws, and those are labels. Here's what the old hw was:

-MA

11-23-10 Elevator problem

We started out in class with going over the blogging rules:

• You must comment twice a month


• November and December are going to be combined, so you have enough time to make your tow comments.
  
• The comments should be either a question or correction.


• Answering a question counts as a comment.


• Your comment should be on a recent blog, otherwise no one will see it and respond.
  

The picture is what a bar graph would look like.

Next we began to work on a few problems with the bar graph packet.

It was: $20 in your wallet, $60 int he bank, and $20 pocket.

If you take $20 out of the bank, and put it in your pocket what would the bar graph look like now.

We would then draw a picture of the change. This is what the rest of the bar graph packet was like.

Then we got into groups, mine was going over the elevator problem.


Say the elevator is 1000 N and Mary is 100 N the weight now is 1100 N the elevator height is 10 meters, how can you figure out how much work was done?


Force* displacement=work


1100* 20= 22000 J

We got 1100 form the weight of Mary and the elevator, and we got 20 because we drew a picture to help us figure out how much distance the elevator would have to go..


Next we had to figure it out if Marys twin sister was on it, we assume she weighs the same.
Mary is 100 pounds, and her twin is 100 pounds

1200*20= 24000

N=Force
Meters= displacement

If we went on the elevator for 4 floors instead of 3, it would be:

1100*30= 33000

1100 because of the weight of the elevator and Mary, and 30 because of the amount of meters between the floor of the first floor and third.

Something I am a little bit confused on is how to make an integer statement. If anyone wants to comment and tell me how, that would be good.

KK

Bar Charts

Thursday, November 18

We started the class by going over the homwork.

The homework problem was:
Eugenia slowly lifts a box by exerting a constant force of 5n. She moves the box from the ground up onto the table, which is 1m high.

Here are the questions on the homework:
1. Draw a picture of intial and final state for the box while she is lifting it.

2. Calculate the work Eugenia has to do in order to lift the box onto the table.

3. Dicuss the energy transformation and write a number sentence to express what occured.

4. Suppose Exerted a larger amount of force on the box at the beginning. What would she have to do to get the box to stop when it got to the table?

We also discussed this question:
Mary rides in an elevator from the first floor to the third floor. Answer the following questions.

Here are the questins:
1. Sketch the intial and final states, and then identify the system.

2. Make a reasonable approximation for the force applied and the distance between the floors in the building.

3. Write an integer statement for the work the elevator does to lift mary to the 3rd floor. Find the work.

4. How much work would the elevator have to do if marys twin sister joined her?

5. How much work would the elevator have to do if mary decided to go to the 4th floor instead? (find the work for both cases: with and without her sister)

-SA

November 17th Wednesday Period 2 (Spring Story)

We started by discussing the homework. We had to describe changes in energy in a story.

1. The spring is pushed down

2. then its released and shoots

3. then it stops going upward and is in midair.

4. it next starts to drop

5. lastly it is caught

On the white boards we wrote the energy transfers for each step and discussed it as a group.

1. We agreed that there was positive work done that transfered it from no energy to elastic potential energy.

2. For this one the spring changed from elastic potential energy to kinetic energy.

3. No the spring loses all of its kinetic energy but has gravitational potentioal energy.

4. The spring loses gravitational potentioal and does downward gaining kinetic energy.

5. Finally the spring is caught where there is negative work aplied to the spring to make ot stop.

We next lodoked at a table with various amounts of force, displacement an work.

We instantly saw that the force times the displacement equals work. Mr. Finley then told us to think of what negative work is. Many groups came up with the idea that negative work is the opposite of work such as negative kinetic energy would be slowing something down or stopping it.

-JP

Period 2 Energy and Systems

Today we are going over the types of energy (gravitational potential, elastic potential, internal, kinetic). We are figuring out what work is being done to these situations:


Person dragged along the ground --> work: thing that is dragging the person
INTERNAL ENERGY system: person, ground, earth

0 J + 5 J = 5 J (started with no energy and gained 5 J of energy)

The ground needs to be in the system because it causes friction on the ground to heat it up. The earth also has to be in the sytem.

Hot air balloon rising into the air --> work: hot air or fire GRAVITATIONAL
system: earth, balloon POTENTIAL

50 J + 10 J (started in the air and increased height by 10 J)

Person on a pogo stick --> work: earth, pogo stick
system: pogo stick ELASTIC ENERGY

I'm not sure about this one but i think it would be: 5 J + 5 J = 10 J because you bounce up and down each time it is not like going down a hill and increasing energy.

You need to have the pogo stick in the system because it wouldnt have springiness (elastic energy) without it.

Car falls off of a cliff --> work: earth system: car KINETIC ENERGY

10 J (driving) + -5 J (falling negative work) = 5 J

I am a little confused on how you would find the equation for something like the pogo stick problem so can anyone tell me what they think it would be? Thanks

EE

11/12/10

First, we went over a few things from yesterday that we didn't get to. We first talked about the homework from a few days ago having to do with the cart on the ramp. The whole process was as follows:

First, the spring sprang the car to the edge of the ramp.

Then, the cart fell off the ramp.

Next, we went over last night's homework. As a group, we had to write our idea of an example of the following: Positive work that causes an increase in the elastic potential of the system. We had these ideas:

---Slinghot Number Sentence: 5+4=9

---Treadmill Number Sentence: 5+4=9

---Rubber band Number Sentence: 5+4=9

Mr. Finley's: Kinetic to Elastic

System: Person, Trampoline

His situation: A person speeding down very fast onto a trampoline that stretches.

20 Jewels= 20 Jewels

Jewels: A unit for energy

JP table idea: Gravitational potential energy in the system is converted to internal energy

A rock is pulled down on a rubber band.

System: Rubberband, Person, Rock

gravity+ -2 gravity+ 2 elastic= 2 elastic

MP table idea: Positive work to kinetic energy

Person pushing a cart

0 units+ 2 units

System= Surface where cart is pushed

DB table idea: Positve work to gravitational energy of the system

A ball falling off of a table

Couldn't come up with an equation

System: Ball

AL table idea: Gravitational potential energy in the system is converted to internal energy.

When meteorites get pulled to earth, they warm up as they go through the atmoshpere.

5 unites of energy+0 units of energy= 5 units of converted energy.

The earth/atmosphere does the work

JF table: Kinetic coverted to grav. potential energy

A kid climbing up a diving board ladder but not jumping up

3+2 +-5+6=6

System: Diving board, Ladder, Earth

This is important because it is the basic facts of this unit. We are going to have to build on all of these different types of energy, so it is a good thing that we are getting familiar with all of them.

Website

EC

Today in class we talked about the five different types of energy. The five of energy are:

• Nuclear Energy
• Light Energy
• Mechanical Energy
• Electrical Energy
• Chemical Energy

We specifically talked about how these types of energy can transform into different types of energy. For example, a crank radio changes mechanical energy into electric energy. The mechanical energy is when you turn the crank and the electric energy is when the radio turns on and finds radio waves and then projects the sound out of itself.
Next in class we talked about the types of mechanical energy which were:

• Kinetic Energy
• Internal Energy
• Gravitational Potential Energy
• Elastic Potential Energy

We then reviewed our homework from Monday and in the first four questions we switched our made names for the situations and inserted the scientific names. The answers were:

a) The external force caused the block to move higher above the Earth’s surface.
Gravitational Potential Energy
b) The external force caused the cart to move faster and faster.
Kinetic Energy
c) The external force caused the slingshot to stretch.
Elastic Energy
d) The external force caused the surfaces of the touching objects to warm.
Internal Energy

During the discussion about those questions we decided that Gravitational Potential Energy meant that gravity had a chance to pull it down to the ground. We also found out that Kinetic Energy was the speeding up of an object not the moving of an object. If you have trouble with this concept just think of when Doc. Fin pushed MK across the room and that it was only Kinetic Energy when MK was being pushed because once Doc. Fin let go negative force was starting to be applied.

Then we answered the first 2 questions of the next section.

Examine the picture to the left. One of your classmates says, “When the car gets to the edge it will have ‘the ability to fall’ or ‘falling ability.’”

a) If the Earth weren’t there, would the car still have “falling ability?” Explain.

b) Should we include or exclude the Earth with the car when we analyze this problem?

For the first question we said that if the Earth wasn’t there than the car wouldn’t have falling ability because the Gravitational Potential Energy that affected the car would be gone. The next question’s answer is that we should include the Earth with the car when we analyze the problem because our results from the previous question show that the Earth is what gives the car falling ability.

Lastly before the bell rang we discovered that every mass has a gravitational pull these masses could be as big as the earth or a small as a chair.

-DB

November 8th, 2010 -Energy Reminders For Test

Today we made a list in our groups to remind us what we know about energy; here's the list. We all tried to remember stuff and we didn't know if its right or wrong. Yet.

Energy

• No mass


• Many forms of energy


• Can never be destroyed


• It never stops going

Then we came together as a class to see what we all came up with;

Brady's Group:

• Light is energy


• Energy cannot die


• You can apply energy


• You can't apply energy to yourself

And a few more.

Yamato's Group:

• Energy has no mass


• Not a state of matter


• Many types of energy


• Can be transferred object to object


• Can be transferred by applying force.

Steven's Group:

• Work is transferring energy to or from our object or system by applying force and having our object displace


• Force; push/pull


• Displacement; change in position

My group:

See the first list.

Alexia's group:

• Isn't matter


• Transferring energy to an item is work


• Doesn't always displace


• Need energy to have chalk smashing ability


• Types of energy; microwaves, UV rays, gamma rays, x-rays.

JayGee(:

**Remember we have a test tomorrow and there's a study session at 7 tomorrow. Study!**

November 3rd, 2010

We didn't do anything, we just went over the homework and played a review game. Have a good four day weekend!!!!!

JG

Chalksmashing Ability

First we went over the homework. To give a big book chalk smashing abillity is to pick up the book first. Force is push or pull. Steven is pulling the book upward. The displacement of the book is upward. When the book is risen upward it is given chalksmashing abillity because the displacement and the force are going in the same direction. When the book is just lying on the counter it does not have chalksmashing abillity because there is no chalksmashing ability. For a cart to smash the chalk it has to be pushed toward the chalk to give it the chalk smashing abillity. When the sling shot is pulled back and the dispacment is backwarsds. A pattern is that went the force and the displacement are going in the same direction. But when the force and the displacement are not going in the same direction it does not have chalksmashing abillity. When Josh pushes a cart and Jenna stops it it gives the cart no chalk smashing abillity. Before Jenna touched the cart the displacement was going to the left and when jenna started to push the force went in the other direction it lost it's chalksmashing abillity because the force and the displacement are going in differnt directions, But when the force and displacement are in opposite directions it loses chalk smashing ability. When we do things to the book and the cart we are transfuring energey to the object by applying force and causing displacement. The reason why we can't pick each other up is That we cant transfer energy to ourselves.
-Anthony M.

Light Review/Chalk experiment

Today in class, we started by checking our homework from last Friday and from the weekend. We were suppose to play a review game using the questions we came up with, but many of the questions where not what the teacher was expecting.

Than we decided to go over the discovery of Newton.

The question based on Newton were:
What happens when white light goes through a prism?

People answered that white light would spread in the prism as it bends and since white light is made up of many colors, when it slows down in the prism, many colors appear.

We discussed about how the different colors have different speed and bend more or less


Than we discussed why this doesn't happen with laser
We thought that this happens because the light of the laser is not white but red.

Next we thought about why do we see the object's color? (why is the sweater orange and why is that sweater blue?)
Light hits the object and goes into your eye,
when the white light hits the orange sweater, only the orange light bounces off and other colors get absorbed
We thought about the time we were observing the laser and thought about how when the laser is shined at a black poster, the laser becomes less visible than when we shine it on an orange poster.

We could test the absorption by placing a black colored paper and a white color paper under a glass of water and see what the temperature of the water is.


Than we asked our selves, where do we see the prism effect in real life?
After rain we would see a rainbow we would see the prism and white light effect. This happens because the sun acts as the white light and the moisture in the air would act like a prism and bends the white light

What are the other types of energy?
white light
UV rays
microwaves
x-rays
inferred

Towards the end of class, we placed a piece of chalk under a dictionary and we thought about what would we have to do in order to smash the piece of chalk using the dictionary.

We said that if we drop a book from a distance, the chalk would break. The dictionary would be more able to smash the chalk when it is farther away from the chalk. One student stood on a chair and dropped the book and the chalk did smash

by AT