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